2025-04-04 14:23:38 +03:00
8093 changed files with 390927 additions and 716211 deletions
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@ -396,8 +396,8 @@ jobs:
            openwrt: "target=sunxi subtarget=cortexa53"
            target_cpu: arm64
            extra: 'arm_cpu="cortex-a53" build_static=true use_allocator_shim=false use_partition_alloc=false'
-            openwrt_release: '24.10.0'
-            openwrt_gcc_ver: '13.3.0'
+            openwrt_release: '23.05.0'
+            openwrt_gcc_ver: '12.3.0'
          - arch: aarch64_cortex-a72
            openwrt: "target=mvebu subtarget=cortexa72"
            target_cpu: arm64
@ -406,14 +406,8 @@ jobs:
            openwrt: "target=mvebu subtarget=cortexa72"
            target_cpu: arm64
            extra: 'arm_cpu="cortex-a72" build_static=true use_allocator_shim=false use_partition_alloc=false'
-            openwrt_release: '24.10.0'
-            openwrt_gcc_ver: '13.3.0'
-          - arch: aarch64_cortex-a76
-            openwrt: "target=bcm27xx subtarget=bcm2712"
-            target_cpu: arm64
-            extra: 'arm_cpu="cortex-a76"'
-            openwrt_release: '24.10.0'
-            openwrt_gcc_ver: '13.3.0'
+            openwrt_release: '23.05.0'
+            openwrt_gcc_ver: '12.3.0'
          - arch: aarch64_generic
            openwrt: "target=layerscape subtarget=armv8_64b"
            target_cpu: arm64
@ -421,8 +415,8 @@ jobs:
            openwrt: "target=layerscape subtarget=armv8_64b"
            target_cpu: arm64
            extra: "build_static=true use_allocator_shim=false use_partition_alloc=false"
-            openwrt_release: '24.10.0'
-            openwrt_gcc_ver: '13.3.0'
+            openwrt_release: '23.05.0'
+            openwrt_gcc_ver: '12.3.0'
          - arch: arm_arm1176jzf-s_vfp
            openwrt: "target=brcm2708 subtarget=bcm2708"
            target_cpu: arm
@ -453,8 +447,8 @@ jobs:
            openwrt: "target=sunxi subtarget=cortexa7"
            target_cpu: arm
            extra: 'arm_version=0 arm_cpu="cortex-a7" arm_fpu="neon-vfpv4" arm_float_abi="hard" arm_use_neon=true build_static=true use_allocator_shim=false use_partition_alloc=false'
-            openwrt_release: '24.10.0'
-            openwrt_gcc_ver: '13.3.0'
+            openwrt_release: '23.05.0'
+            openwrt_gcc_ver: '12.3.0'
          - arch: arm_cortex-a7_vfpv4
            openwrt: "target=at91 subtarget=sama7"
            target_cpu: arm
@ -473,8 +467,8 @@ jobs:
            openwrt: "target=bcm53xx subtarget=generic"
            target_cpu: arm
            extra: 'arm_version=0 arm_cpu="cortex-a9" arm_float_abi="soft" arm_use_neon=false build_static=true use_allocator_shim=false use_partition_alloc=false'
-            openwrt_release: '24.10.0'
-            openwrt_gcc_ver: '13.3.0'
+            openwrt_release: '23.05.0'
+            openwrt_gcc_ver: '12.3.0'
          - arch: arm_cortex-a9_neon
            openwrt: "target=imx6 subtarget=generic"
            target_cpu: arm
@ -499,8 +493,8 @@ jobs:
            openwrt: "target=ramips subtarget=rt305x"
            target_cpu: mipsel
            extra: 'mips_arch_variant="r2" mips_float_abi="soft" build_static=true use_allocator_shim=false use_partition_alloc=false'
-            openwrt_release: '24.10.0'
-            openwrt_gcc_ver: '13.3.0'
+            openwrt_release: '23.05.0'
+            openwrt_gcc_ver: '12.3.0'
          - arch: mipsel_mips32
            openwrt: "target=brcm47xx subtarget=legacy"
            target_cpu: mipsel
--- a/2
+++ b/2
@ -1 +1 @@
-135.0.7049.38
+132.0.6834.79
--- a/README.md
+++ b/README.md
@ -82,6 +82,7 @@ Or `quic://user:pass@example.com`, if it works better. See also [parameter usage
 * [v2rayN](https://github.com/2dust/v2rayN), GUI client, Windows
 * [NekoBox for Android](https://github.com/MatsuriDayo/NekoBoxForAndroid), Proxy toolchain, Android
 * [NekoRay / NekoBox For PC](https://github.com/MatsuriDayo/nekoray), Qt based GUI, Windows, Linux
+* [Yet Another Shadow Socket](https://github.com/Chilledheart/yass), NaïveProxy-compatible forward proxy, Android, iOS, Windows, macOS, Linux, FreeBSD

 ## Notes for downstream

--- a/src/.gn
+++ b/src/.gn
@ -90,7 +90,7 @@ no_check_targets = [
  "//v8:v8_libplatform",  # 2 errors
 ]

-# These are the list of GN files that run exec_script. This allowlist exists
+# These are the list of GN files that run exec_script. This whitelist exists
 # to force additional review for new uses of exec_script, which is strongly
 # discouraged.
 #
@ -145,11 +145,11 @@ no_check_targets = [
 #      this situation much easier to create. if the build always lists the
 #      files and passes them to a script, it will always be correct.

-exec_script_allowlist =
-    build_dotfile_settings.exec_script_allowlist +
+exec_script_whitelist =
+    build_dotfile_settings.exec_script_whitelist +
    angle_dotfile_settings.exec_script_whitelist +
    [
-      # Allowlist entries for //build should go into
+      # Whitelist entries for //build should go into
      # //build/dotfile_settings.gni instead, so that they can be shared
      # with other repos. The entries in this list should be only for files
      # in the Chromium repo outside of //build.
--- a/src/AUTHORS
+++ b/src/AUTHORS
@ -118,7 +118,6 @@ Andreas Papacharalampous <andreas@apap04.com>
 Andrei Borza <andrei.borza@gmail.com>
 Andrei Parvu <andrei.prv@gmail.com>
 Andrei Parvu <parvu@adobe.com>
-Andrei Volykhin <andrei.volykhin@gmail.com>
 Andres Salomon <dilinger@queued.net>
 Andreu Botella <andreu@andreubotella.com>
 Andrew Boyarshin <andrew.boyarshin@gmail.com>
@ -313,7 +312,6 @@ Daniel Lockyer <thisisdaniellockyer@gmail.com>
 Daniel Nishi <dhnishi@gmail.com>
 Daniel Platz <daplatz@googlemail.com>
 Daniel Playfair Cal <daniel.playfair.cal@gmail.com>
-Daniel Richard G. <iskunk@gmail.com>
 Daniel Shaulov <dshaulov@ptc.com>
 Daniel Trebbien <dtrebbien@gmail.com>
 Daniel Waxweiler <daniel.waxweiler@gmail.com>
@ -331,10 +329,8 @@ Darshini KN <kn.darshini@samsung.com>
 Dave Vandyke <kzar@kzar.co.uk>
 David Benjamin <davidben@mit.edu>
 David Brown <develop.david.brown@gmail.com>
-David Cernoch <dcernoch@uplandsoftware.com>
 David Davidovic <david@davidovic.io>
 David Erceg <erceg.david@gmail.com>
-David Faden <dfaden@gmail.com>
 David Fox <david@davidjfox.com>
 David Futcher <david.mike.futcher@gmail.com>
 David Jin <davidjin@amazon.com>
@ -351,7 +347,6 @@ Dax Kelson <dkelson@gurulabs.com>
 Dean Leitersdorf <dean.leitersdorf@gmail.com>
 Debadree Chatterjee <debadree333@gmail.com>
 Debashish Samantaray <d.samantaray@samsung.com>
-Debin Zhang <debinzhang3@gmail.com>
 Debug Wang <debugwang@tencent.com>
 Deep Shah <deep.shah@samsung.com>
 Deepak Dilip Borade <deepak.db@samsung.com>
@ -371,7 +366,6 @@ Diana Suvorova <diana.suvorova@gmail.com>
 Diego Fernández Santos <agujaydedal@gmail.com>
 Diego Ferreiro Val <elfogris@gmail.com>
 Dillon Sellars <dill.sellars@gmail.com>
-Dingming Liu <liudingming@bytedance.com>
 Divya Bansal <divya.bansal@samsung.com>
 Dmitry Shachnev <mitya57@gmail.com>
 Dmitry Sokolov <dimanne@gmail.com>
@ -508,7 +502,6 @@ Hansel Lee <mr.hansel.lee@gmail.com>
 Hanwen Zheng <eserinc.z@gmail.com>
 Hao Li <hao.x.li@intel.com>
 Haojian Wu <hokein.wu@gmail.com>
-Haoran Tang <haoran.tang.personal@gmail.com>
 Haoxuan Zhang <zhanghaoxuan.59@bytedance.com>
 Hari Singh <hari.singh1@samsung.com>
 Harpreet Singh Khurana <harpreet.sk@samsung.com>
@ -630,10 +623,8 @@ Jared Wein <weinjared@gmail.com>
 Jari Karppanen <jkarp@amazon.com>
 Jason Gronn <jasontopia03@gmail.com>
 Javayhu <javayhu@gmail.com>
-Jay Kapadia <jaykapadia389@gmail.com>
 Jay Oster <jay@kodewerx.org>
 Jay Soffian <jaysoffian@gmail.com>
-Jay Yang <sjyang1126@gmail.com>
 Jeado Ko <haibane84@gmail.com>
 Jeffrey C <jeffreyca16@gmail.com>
 Jeffrey Yeung <jeffrey.yeung@poly.com>
@ -732,7 +723,6 @@ Joseph Lolak <joseph.lolak@samsung.com>
 Josh Triplett <josh.triplett@intel.com>
 Josh Triplett <josh@joshtriplett.org>
 Joshua Lock <joshua.lock@intel.com>
-Joshua Olaoye <joshuaolaoye46@gmail.com>
 Joshua Roesslein <jroesslein@gmail.com>
 Josué Ratelle <jorat1346@gmail.com>
 Josyula Venkat Narasimham <venkat.nj@samsung.com>
@ -782,7 +772,6 @@ Kangyuan Shu <kangyuan.shu@intel.com>
 Karan Thakkar <karanjthakkar@gmail.com>
 Karel Král <kralkareliv@gmail.com>
 Karl <karlpolicechromium@gmail.com>
-Karl Piper <karl4piper@gmail.com>
 Kartikey Bhatt <kartikey@amazon.com>
 Kaspar Brand <googlecontrib@velox.ch>
 Kaushalendra Mishra <k.mishra@samsung.com>
@ -942,7 +931,6 @@ Martin Persson <mnpn03@gmail.com>
 Martin Rogalla <martin@martinrogalla.com>
 Martina Kollarova <martina.kollarova@intel.com>
 Martino Fontana <tinozzo123@gmail.com>
-Marvin Giessing <marvin.giessing@gmail.com>
 Masahiro Yado <yado.masa@gmail.com>
 Masaru Nishida <msr.i386@gmail.com>
 Masayuki Wakizaka <mwakizaka0108@gmail.com>
@ -953,7 +941,6 @@ Mathieu Meisser <mmeisser@logitech.com>
 Matt Arpidone <mma.public@gmail.com>
 Matt Fysh <mattfysh@gmail.com>
 Matt Harding <majaharding@gmail.com>
-Matt Jolly <kangie@gentoo.org>
 Matt Strum <mstrum@amazon.com>
 Matt Zeunert <matt@mostlystatic.com>
 Matthew "strager" Glazar <strager.nds@gmail.com>
@ -977,12 +964,10 @@ Mc Zeng <zengmcong@gmail.com>
 Md Abdullah Al Alamin <a.alamin.cse@gmail.com>
 Md. Hasanur Rashid <hasanur.r@samsung.com>
 Md Hasibul Hasan <hasibulhasan873@gmail.com>
-Md Hasibul Hasan <hasibul.h@samsung.com>
 Md Jobed Hossain <jobed.h@samsung.com>
 Md Raiyan bin Sayeed <mrbsayee@uwaterloo.ca>
 Md. Sadiqul Amin <sadiqul.amin@samsung.com>
 Md Sami Uddin <md.sami@samsung.com>
-Mego Tan <tannal2409@gmail.com>
 Merajul Arefin <merajularefin@gmail.com>
 Micha Hanselmann <micha.hanselmann@gmail.com>
 Michael Cirone <mikecirone@gmail.com>
@ -1010,7 +995,6 @@ Milko Leporis <milko.leporis@imgtec.com>
 Milton Chiang <milton.chiang@mediatek.com>
 Milutin Smiljanic <msmiljanic.gm@gmail.com>
 Minchul Kang <tegongkang@gmail.com>
-Ming Lei <minggeorgelei@gmail.com>
 Mingeun Park <mindal99546@gmail.com>
 Minggang Wang <minggang.wang@intel.com>
 Mingmin Xie <melvinxie@gmail.com>
@ -1030,7 +1014,6 @@ Mohamed Mansour <m0.interactive@gmail.com>
 Mohamed Hany Youns <mohamedhyouns@gmail.com>
 Mohammad Azam <m.azam@samsung.com>
 MohammadSabri <mohammad.kh.sabri@exalt.ps>
-Mohammed Ashraf <mohammedashraf4599@gmail.com>
 Mohammed Wajahat Ali Siddiqui <wajahat.s@samsung.com>
 Mohan Reddy <mohan.reddy@samsung.com>
 Mohit Bhalla <bhallam@amazon.com>
@ -1312,7 +1295,6 @@ Serhii Matrunchyk <sergiy.matrunchyk@gmail.com>
 Seshadri Mahalingam <seshadri.mahalingam@gmail.com>
 Seungkyu Lee <zx6658@gmail.com>
 Sevan Janiyan <venture37@geeklan.co.uk>
-Shaheen Fazim <fazim.pentester@gmail.com>
 Shahriar Rostami <shahriar.rostami@gmail.com>
 Shail Singhal <shail.s@samsung.com>
 Shane Hansen <shanemhansen@gmail.com>
@ -1470,7 +1452,6 @@ Tom Harwood <tfh@skip.org>
 Tomas Popela <tomas.popela@gmail.com>
 Tomasz Edward Posłuszny <tom@devpeer.net>
 Tony Shen <legendmastertony@gmail.com>
-Topi Lassila <tolassila@gmail.com>
 Torsten Kurbad <google@tk-webart.de>
 Toshihito Kikuchi <leamovret@gmail.com>
 Toshiaki Tanaka <zokutyou2@gmail.com>
@ -1522,7 +1503,6 @@ Wojciech Bielawski <wojciech.bielawski@gmail.com>
 Wang Chen <wangchen20@iscas.ac.cn>
 Wang Chen <unicornxw@gmail.com>
 Wang Weiwei <wangww@dingdao.com>
-Wang Zirui <kingzirvi@gmail.com>
 Wangyang Dai <jludwy@gmail.com>
 Wanming Lin <wanming.lin@intel.com>
 Wei Li <wei.c.li@intel.com>
@ -1631,7 +1611,6 @@ Zeqin Chen <talonchen@tencent.com>
 Zhanbang He <hezhanbang@gmail.com>
 Zhang Hao <zhanghao.m@bytedance.com>
 Zhang Hao <15686357310a@gmail.com>
-Zhao Qin <qzmiss@gmail.com>
 Zhaoming Jiang <zhaoming.jiang@intel.com>
 Zhaoze Zhou <zhaoze.zhou@partner.samsung.com>
 Zheda Chen <zheda.chen@intel.com>
@ -1657,7 +1636,6 @@ Zsolt Borbely <zsborbely.u-szeged@partner.samsung.com>
 迷渡 <justjavac@gmail.com>
 郑苏波 (Super Zheng) <superzheng@tencent.com>
 一丝 (Yisi) <yiorsi@gmail.com>
-林训杰 (XunJie Lin) <wick.linxunjie@gmail.com>
 # Please DO NOT APPEND here. See comments at the top of the file.
 # END individuals section.

@ -1687,7 +1665,6 @@ EngFlow, Inc. <*@engflow.com>
 Estimote, Inc. <*@estimote.com>
 Google Inc. <*@google.com>
 Grammarly, Inc. <*@grammarly.com>
-Here Inc. <*@here.io>
 Hewlett-Packard Development Company, L.P. <*@hp.com>
 HyperConnect Inc. <*@hpcnt.com>
 IBM Inc. <*@*.ibm.com>
--- a/src/BUILD.gn
+++ b/src/BUILD.gn
@ -12,6 +12,7 @@ import("//build/config/compiler/compiler.gni")
 import("//build/config/cronet/config.gni")
 import("//build/config/dcheck_always_on.gni")
 import("//build/config/features.gni")
+import("//build/config/ios/config.gni")
 import("//build/config/rust.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/ui.gni")
--- a/src/DEPS
+++ b/src/DEPS
--- a/src/base/BUILD.gn
+++ b/src/base/BUILD.gn
@ -25,9 +25,12 @@ import("//build/buildflag_header.gni")
 import("//build/config/arm.gni")
 import("//build/config/c++/c++.gni")
 import("//build/config/cast.gni")
+import("//build/config/chromeos/ui_mode.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/cronet/config.gni")
 import("//build/config/dcheck_always_on.gni")
+import("//build/config/features.gni")
+import("//build/config/ios/config.gni")
 import("//build/config/logging.gni")
 import("//build/config/nacl/config.gni")
 import("//build/config/profiling/profiling.gni")
@ -40,9 +43,6 @@ import("//build/util/process_version.gni")
 import("//build_overrides/build.gni")

 if (is_ios) {
-  # Used to access target_environment and target_platform.
-  import("//build/config/apple/mobile_config.gni")
-
  # Used to access ios_is_app_extension variable definition.
  import("//build/config/ios/ios_sdk.gni")
 }
@ -170,6 +170,8 @@ component("base") {
    "allocator/dispatcher/internal/dispatch_data.h",
    "allocator/dispatcher/internal/dispatcher_internal.h",
    "allocator/dispatcher/internal/tools.h",
+    "allocator/dispatcher/memory_tagging.cc",
+    "allocator/dispatcher/memory_tagging.h",
    "allocator/dispatcher/notification_data.h",
    "allocator/dispatcher/reentry_guard.cc",
    "allocator/dispatcher/reentry_guard.h",
@ -180,7 +182,6 @@ component("base") {
    "at_exit.h",
    "atomic_ref_count.h",
    "atomic_sequence_num.h",
-    "atomicops.cc",
    "atomicops.h",
    "atomicops_internals_atomicword_compat.h",
    "atomicops_internals_portable.h",
@ -212,7 +213,6 @@ component("base") {
    "compiler_specific.h",
    "component_export.h",
    "containers/adapters.h",
-    "containers/adapters_internal.h",
    "containers/buffer_iterator.h",
    "containers/checked_iterators.h",
    "containers/circular_deque.h",
@ -243,6 +243,8 @@ component("base") {
    "containers/unique_ptr_adapters.h",
    "containers/util.h",
    "containers/vector_buffer.h",
+    "cpu_reduction_experiment.cc",
+    "cpu_reduction_experiment.h",
    "critical_closure.h",
    "dcheck_is_on.h",
    "debug/alias.cc",
@ -340,7 +342,6 @@ component("base") {
    "macros/uniquify.h",
    "memory/aligned_memory.cc",
    "memory/aligned_memory.h",
-    "memory/asan_interface.h",
    "memory/free_deleter.h",
    "memory/memory_pressure_listener.cc",
    "memory/memory_pressure_listener.h",
@ -366,6 +367,7 @@ component("base") {
    "memory/raw_ptr_cast.h",
    "memory/raw_ptr_exclusion.h",
    "memory/raw_ref.h",
+    "memory/raw_scoped_refptr_mismatch_checker.h",
    "memory/raw_span.h",
    "memory/read_only_shared_memory_region.cc",
    "memory/read_only_shared_memory_region.h",
@ -402,8 +404,6 @@ component("base") {
    "memory/weak_ptr.h",
    "memory/writable_shared_memory_region.cc",
    "memory/writable_shared_memory_region.h",
-    "message_loop/io_watcher.cc",
-    "message_loop/io_watcher.h",
    "message_loop/message_pump.cc",
    "message_loop/message_pump.h",
    "message_loop/message_pump_default.cc",
@ -457,7 +457,6 @@ component("base") {
    "metrics/record_histogram_checker.h",
    "metrics/sample_map.cc",
    "metrics/sample_map.h",
-    "metrics/sample_map_iterator.h",
    "metrics/sample_vector.cc",
    "metrics/sample_vector.h",
    "metrics/single_sample_metrics.cc",
@ -517,7 +516,6 @@ component("base") {
    "process/process_info.h",
    "process/set_process_title.cc",
    "process/set_process_title.h",
-    "profiler/core_unwinders.h",
    "profiler/frame.cc",
    "profiler/frame.h",
    "profiler/metadata_recorder.cc",
@ -528,7 +526,6 @@ component("base") {
    "profiler/periodic_sampling_scheduler.h",
    "profiler/profile_builder.h",
    "profiler/register_context.h",
-    "profiler/register_context_registers.h",
    "profiler/sample_metadata.cc",
    "profiler/sample_metadata.h",
    "profiler/sampling_profiler_thread_token.cc",
@ -547,19 +544,19 @@ component("base") {
    "profiler/stack_unwind_data.h",
    "profiler/suspendable_thread_delegate.h",
    "profiler/thread_delegate.h",
-    "profiler/thread_group_profiler.cc",
-    "profiler/thread_group_profiler.h",
    "profiler/thread_group_profiler_client.h",
    "profiler/unwinder.cc",
    "profiler/unwinder.h",
    "rand_util.cc",
    "rand_util.h",
+    "ranges/algorithm.h",
+    "ranges/from_range.h",
+    "ranges/functional.h",
+    "ranges/ranges.h",
    "run_loop.cc",
    "run_loop.h",
    "sampling_heap_profiler/lock_free_address_hash_set.cc",
    "sampling_heap_profiler/lock_free_address_hash_set.h",
-    "sampling_heap_profiler/lock_free_bloom_filter.cc",
-    "sampling_heap_profiler/lock_free_bloom_filter.h",
    "sampling_heap_profiler/poisson_allocation_sampler.cc",
    "sampling_heap_profiler/poisson_allocation_sampler.h",
    "sampling_heap_profiler/sampling_heap_profiler.cc",
@ -584,7 +581,6 @@ component("base") {
    "strings/abseil_string_number_conversions.cc",
    "strings/abseil_string_number_conversions.h",
    "strings/cstring_view.h",
-    "strings/durable_string_view.h",
    "strings/escape.cc",
    "strings/escape.h",
    "strings/latin1_string_conversions.cc",
@ -595,14 +591,12 @@ component("base") {
    "strings/pattern.h",
    "strings/safe_sprintf.cc",
    "strings/safe_sprintf.h",
-    "strings/span_printf.h",
    "strings/strcat.cc",
    "strings/strcat.h",
    "strings/strcat_internal.h",
    "strings/string_number_conversions.cc",
    "strings/string_number_conversions.h",
    "strings/string_number_conversions_internal.h",
-    "strings/string_slice.h",
    "strings/string_split.cc",
    "strings/string_split.h",
    "strings/string_split_internal.h",
@ -633,8 +627,6 @@ component("base") {
    "supports_user_data.h",
    "synchronization/atomic_flag.cc",
    "synchronization/atomic_flag.h",
-    "synchronization/cancelable_event.cc",
-    "synchronization/cancelable_event.h",
    "synchronization/condition_variable.h",
    "synchronization/lock.cc",
    "synchronization/lock.h",
@ -690,6 +682,7 @@ component("base") {
    "task/sequence_manager/enqueue_order_generator.h",
    "task/sequence_manager/fence.cc",
    "task/sequence_manager/fence.h",
+    "task/sequence_manager/lazily_deallocated_deque.h",
    "task/sequence_manager/sequence_manager.cc",
    "task/sequence_manager/sequence_manager.h",
    "task/sequence_manager/sequence_manager_impl.cc",
@ -868,8 +861,6 @@ component("base") {
    "trace_event/heap_profiler_allocation_context.h",
    "trace_event/heap_profiler_allocation_context_tracker.cc",
    "trace_event/heap_profiler_allocation_context_tracker.h",
-    "trace_event/histogram_scope.cc",
-    "trace_event/histogram_scope.h",
    "trace_event/memory_allocator_dump_guid.cc",
    "trace_event/memory_allocator_dump_guid.h",
    "trace_event/named_trigger.cc",
@ -879,7 +870,6 @@ component("base") {
    "traits_bag.h",
    "tuple.h",
    "types/always_false.h",
-    "types/cxx23_from_range.h",
    "types/cxx23_is_scoped_enum.h",
    "types/cxx23_to_underlying.h",
    "types/expected.h",
@ -893,14 +883,11 @@ component("base") {
    "types/optional_ref.h",
    "types/optional_util.h",
    "types/pass_key.h",
-    "types/same_as_any.h",
    "types/strong_alias.h",
    "types/supports_ostream_operator.h",
-    "types/supports_to_string.h",
    "types/to_address.h",
    "types/token_type.h",
    "types/variant_util.h",
-    "types/zip.h",
    "unguessable_token.cc",
    "unguessable_token.h",
    "uuid.cc",
@ -1037,8 +1024,8 @@ component("base") {
  # to provide the appropriate `#define` here.
  defines += [ "IS_RAW_PTR_IMPL" ]

-  # native_unwinder_android is split into a separate target to avoid pulling
-  # libunwindstack dependencies into cronet's base.
+  # native_unwinder_android is intended for use solely via a dynamic feature
+  # module, to avoid increasing Chrome's executable size.
  assert_no_deps = [ ":native_unwinder_android" ]

  public_deps = [
@ -1062,13 +1049,10 @@ component("base") {
    "//base/numerics:base_numerics",
    "//base/third_party/icu",
    "//build:chromecast_buildflags",
+    "//build:chromeos_buildflags",
    "//third_party/abseil-cpp:absl",
  ]

-  # TODO(crbug.com/354842935): Remove this dependency once other modules don't
-  # accidentally (transitively) depend on it anymore.
-  public_deps += [ "//build:chromeos_buildflags" ]
-
  # Needed for <atomic> if using newer C++ library than sysroot, except if
  # building inside the cros_sdk environment - use host_toolchain as a
  # more robust check for this.
@ -1116,8 +1100,7 @@ component("base") {
      "android/scoped_hardware_buffer_fence_sync.h",
      "android/scoped_hardware_buffer_handle.cc",
      "android/scoped_hardware_buffer_handle.h",
-      "android/scoped_input_event.cc",
-      "android/scoped_input_event.h",
+      "android/sys_utils.h",
      "debug/stack_trace_android.cc",
      "files/file_util_android.cc",
      "files/scoped_file_android.cc",
@ -1157,12 +1140,18 @@ component("base") {
    # well when doing a component build.
    public_configs = [ ":android_system_libs" ]

+    if (can_unwind_with_cfi_table) {
+      sources += [
+        "trace_event/cfi_backtrace_android.cc",
+        "trace_event/cfi_backtrace_android.h",
+      ]
+    }
    if (current_cpu == "arm") {
      sources += [
-        "profiler/chrome_unwind_info_android_32.cc",
-        "profiler/chrome_unwind_info_android_32.h",
-        "profiler/chrome_unwinder_android_32.cc",
-        "profiler/chrome_unwinder_android_32.h",
+        "profiler/chrome_unwind_info_android.cc",
+        "profiler/chrome_unwind_info_android.h",
+        "profiler/chrome_unwinder_android.cc",
+        "profiler/chrome_unwinder_android.h",
      ]
    }

@ -1188,6 +1177,7 @@ component("base") {
  if (is_robolectric) {
    # Make jni.h available.
    configs += [ "//third_party/jdk" ]
+    deps += [ ":base_robolectric_jni" ]
  }
  if (is_robolectric) {
    sources += [
@ -1196,8 +1186,6 @@ component("base") {
      "android/callback_android.cc",
      "android/callback_android.h",
      "android/command_line_android.cc",
-      "android/int_string_callback.cc",
-      "android/int_string_callback.h",
      "android/java_exception_reporter.cc",
      "android/java_exception_reporter.h",
      "android/jni_android.cc",
@ -1206,8 +1194,6 @@ component("base") {
      "android/jni_array.h",
      "android/jni_bytebuffer.cc",
      "android/jni_bytebuffer.h",
-      "android/jni_callback.cc",
-      "android/jni_callback.h",
      "android/jni_registrar.cc",
      "android/jni_registrar.h",
      "android/jni_string.cc",
@ -1215,13 +1201,8 @@ component("base") {
      "android/jni_utils.cc",
      "android/jni_utils.h",
      "android/jni_weak_ref.h",
-      "android/library_loader/anchor_functions.cc",
-      "android/library_loader/anchor_functions.h",
      "android/library_loader/library_loader_hooks.cc",
      "android/library_loader/library_loader_hooks.h",
-      "android/library_loader/library_prefetcher.cc",
-      "android/library_loader/library_prefetcher.h",
-      "android/library_loader/library_prefetcher_hooks.cc",
      "android/native_uma_recorder.cc",
      "android/scoped_java_ref.h",
      "android/token_android.cc",
@ -1444,7 +1425,6 @@ component("base") {
      "debug/crash_logging.h",
      "debug/stack_trace.cc",
      "debug/stack_trace.h",
-      "files/drive_info.cc",
      "files/drive_info.h",
      "files/file_enumerator.cc",
      "files/file_enumerator.h",
@ -1572,13 +1552,6 @@ component("base") {
    if (is_posix && !is_ios) {
      sources += [ "process/process_posix.cc" ]
    }
-    if (!is_win && !is_chromeos && !is_android && !is_linux) {
-      sources += [ "synchronization/cancelable_event_default.cc" ]
-    }
-
-    if (is_linux || is_chromeos || is_android) {
-      sources += [ "synchronization/cancelable_event_posix.cc" ]
-    }

    if (use_blink) {
      sources += [
@ -1613,12 +1586,8 @@ component("base") {
      ]
    }
    if (use_partition_alloc) {
-      # Add stuff that doesn't work in NaCl or other environments that disable
-      # partition_alloc.
+      # Add stuff that doesn't work in NaCl.
      sources += [
-        "allocator/dispatcher/memory_tagging.cc",
-        "allocator/dispatcher/memory_tagging.h",
-
        # PartitionAlloc uses SpinLock, which doesn't work in NaCl (see below).
        "allocator/miracle_parameter.cc",
        "allocator/miracle_parameter.h",
@ -1628,9 +1597,15 @@ component("base") {
        "allocator/partition_alloc_support.h",
      ]
    }
-    if (use_allocator_shim) {
-      public_deps += [ "allocator/partition_allocator:allocator_shim" ]
-    }
+
+    # Need this to pass gn check, because gn check doesn't see
+    # BUILDFLAG(USE_PARTITION_ALLOC). A linker will remove all
+    # partition_alloc code if use_partition_alloc = false because no code uses
+    # partition_alloc.
+    public_deps += [
+      "allocator/partition_allocator:partition_alloc",
+      "allocator/partition_allocator:raw_ptr",
+    ]
  }

  # Windows.
@ -1677,7 +1652,6 @@ component("base") {
      "process/process_iterator_win.cc",
      "process/process_metrics_win.cc",
      "process/process_win.cc",
-      "profiler/core_unwinders_win.cc",
      "profiler/module_cache_win.cc",
      "profiler/native_unwinder_win.cc",
      "profiler/native_unwinder_win.h",
@ -1698,7 +1672,6 @@ component("base") {
      "strings/string_util_win.h",
      "strings/sys_string_conversions_win.cc",
      "sync_socket_win.cc",
-      "synchronization/cancelable_event_win.cc",
      "synchronization/condition_variable_win.cc",
      "synchronization/lock_impl_win.cc",
      "synchronization/waitable_event_watcher_win.cc",
@ -1741,8 +1714,6 @@ component("base") {
      "win/event_trace_controller.h",
      "win/event_trace_provider.cc",
      "win/event_trace_provider.h",
-      "win/hardware_check.cc",
-      "win/hardware_check.h",
      "win/hstring_reference.cc",
      "win/hstring_reference.h",
      "win/i18n.cc",
@ -1754,12 +1725,10 @@ component("base") {
      "win/message_window.h",
      "win/nt_status.cc",
      "win/nt_status.h",
-      "win/ntsecapi_shim.h",
      "win/object_watcher.cc",
      "win/object_watcher.h",
      "win/patch_util.cc",
      "win/patch_util.h",
-      "win/pdh_shim.h",
      "win/pe_image_reader.cc",
      "win/pe_image_reader.h",
      "win/post_async_results.h",
@ -1778,7 +1747,6 @@ component("base") {
      "win/scoped_co_mem.h",
      "win/scoped_com_initializer.cc",
      "win/scoped_com_initializer.h",
-      "win/scoped_gdi_object.cc",
      "win/scoped_gdi_object.h",
      "win/scoped_handle.cc",
      "win/scoped_handle.h",
@ -1818,13 +1786,10 @@ component("base") {
      "win/variant_vector.h",
      "win/vector.cc",
      "win/vector.h",
-      "win/wbemidl_shim.h",
      "win/win_handle_types.h",
      "win/win_handle_types_list.inc",
      "win/win_util.cc",
      "win/win_util.h",
-      "win/winbase_shim.h",
-      "win/wincred_shim.h",
      "win/wincrypt_shim.h",
      "win/window_enumerator.cc",
      "win/window_enumerator.h",
@ -1838,7 +1803,6 @@ component("base") {
      "win/winrt_foundation_helpers.h",
      "win/winrt_storage_util.cc",
      "win/winrt_storage_util.h",
-      "win/wintrust_shim.h",
      "win/wmi.cc",
      "win/wmi.h",
      "win/wrapped_window_proc.cc",
@ -1894,8 +1858,8 @@ component("base") {
      "apple/call_with_eh_frame.cc",
      "apple/call_with_eh_frame.h",
      "apple/call_with_eh_frame_asm.S",
-      "apple/dispatch_source.cc",
-      "apple/dispatch_source.h",
+      "apple/dispatch_source_mach.cc",
+      "apple/dispatch_source_mach.h",
      "apple/foundation_util.h",
      "apple/foundation_util.mm",
      "apple/mach_logging.cc",
@ -1926,9 +1890,10 @@ component("base") {
      "message_loop/message_pump_apple.h",
      "message_loop/message_pump_apple.mm",
      "native_library_apple.mm",
-      "process/process_metrics_apple.mm",
+      "process/process_metrics_apple.cc",
      "profiler/module_cache_apple.cc",
      "strings/sys_string_conversions_apple.mm",
+      "synchronization/waitable_event_apple.cc",
      "system/sys_info_apple.mm",
      "threading/platform_thread_apple.mm",
      "time/time_apple.mm",
@ -1940,10 +1905,6 @@ component("base") {
      "Foundation.framework",
      "Security.framework",
    ]
-
-    if (!is_ios || !use_blink) {
-      sources += [ "synchronization/waitable_event_apple.cc" ]
-    }
  }

  # Desktop Mac.
@ -2005,11 +1966,10 @@ component("base") {
      "process/port_provider_mac.cc",
      "process/port_provider_mac.h",
      "process/process_handle_mac.cc",
-      "process/process_info_mac.mm",
+      "process/process_info_mac.cc",
      "process/process_iterator_mac.cc",
      "process/process_mac.cc",
      "process/process_metrics_mac.cc",
-      "profiler/core_unwinders_mac.cc",
      "profiler/frame_pointer_unwinder.cc",
      "profiler/frame_pointer_unwinder.h",
      "profiler/stack_sampler_mac.cc",
@ -2052,7 +2012,6 @@ component("base") {
      "power_monitor/power_monitor_device_source_ios.mm",
      "process/process_metrics_ios.cc",
      "process/process_metrics_posix.cc",
-      "profiler/core_unwinders_ios.cc",
      "profiler/stack_sampler_ios.cc",
      "system/sys_info_ios.mm",
    ]
@ -2080,20 +2039,12 @@ component("base") {
        "process/process_handle_mac.cc",
        "process/process_ios.cc",
        "process/process_iterator_mac.cc",
+        "process/process_mac.cc",
        "process/process_posix.cc",
        "sync_socket_posix.cc",
-        "synchronization/waitable_event_posix.cc",
-        "synchronization/waitable_event_watcher_posix.cc",
+        "synchronization/waitable_event_watcher_mac.cc",
      ]

-      if (target_platform == "tvos") {
-        # tvOS apps must be single-process. Build a Process version that does
-        # the bare minimum and does not use Mach ports.
-        sources += [ "process/process_tvos.cc" ]
-      } else {
-        sources += [ "process/process_mac.cc" ]
-      }
-
      # We include launch_mac on simulator builds so unittests can fork.
      if (target_environment == "simulator") {
        sources += [
@ -2116,11 +2067,6 @@ component("base") {
        "message_loop/message_pump_io_ios.cc",
        "message_loop/message_pump_io_ios.h",
      ]
-    } else if (use_blink) {
-      sources += [
-        "message_loop/message_pump_io_ios_libdispatch.cc",
-        "message_loop/message_pump_io_ios_libdispatch.h",
-      ]
    } else {
      sources += [
        "message_loop/message_pump_kqueue.cc",
@ -2250,10 +2196,7 @@ component("base") {
  }

  if ((is_posix && !is_apple && !is_android) || is_fuchsia) {
-    sources += [
-      "profiler/core_unwinders_posix.cc",
-      "profiler/stack_sampler_posix.cc",
-    ]
+    sources += [ "profiler/stack_sampler_posix.cc" ]
  }

  if ((is_posix && !is_apple && !is_android && !is_chromeos) || is_fuchsia) {
@ -2276,7 +2219,10 @@ component("base") {
  if (enable_base_tracing) {
    sources += [
      "trace_event/auto_open_close_event.h",
+      "trace_event/builtin_categories.cc",
      "trace_event/builtin_categories.h",
+      "trace_event/category_registry.cc",
+      "trace_event/category_registry.h",
      "trace_event/heap_profiler.h",
      "trace_event/interned_args_helper.cc",
      "trace_event/interned_args_helper.h",
@ -2303,14 +2249,13 @@ component("base") {
      "trace_event/memory_usage_estimator.cc",
      "trace_event/memory_usage_estimator.h",
      "trace_event/optional_trace_event.h",
-      "trace_event/perfetto_proto_appender.cc",
-      "trace_event/perfetto_proto_appender.h",
      "trace_event/process_memory_dump.cc",
      "trace_event/process_memory_dump.h",
      "trace_event/trace_arguments.cc",
      "trace_event/trace_arguments.h",
      "trace_event/trace_buffer.cc",
      "trace_event/trace_buffer.h",
+      "trace_event/trace_category.h",
      "trace_event/trace_config.cc",
      "trace_event/trace_config.h",
      "trace_event/trace_config_category_filter.cc",
@ -2318,8 +2263,11 @@ component("base") {
      "trace_event/trace_event.h",
      "trace_event/trace_event_impl.cc",
      "trace_event/trace_event_impl.h",
+      "trace_event/trace_event_memory_overhead.cc",
+      "trace_event/trace_event_memory_overhead.h",
      "trace_event/trace_log.cc",
      "trace_event/trace_log.h",
+      "trace_event/trace_log_constants.cc",
      "trace_event/traced_value.cc",
      "trace_event/traced_value.h",
      "trace_event/traced_value_support.h",
@ -2327,6 +2275,8 @@ component("base") {
      "trace_event/tracing_agent.h",
      "trace_event/typed_macros.h",
      "trace_event/typed_macros_embedder_support.h",
+      "trace_event/typed_macros_internal.cc",
+      "trace_event/typed_macros_internal.h",
      "tracing/perfetto_platform.cc",
      "tracing/perfetto_platform.h",
      "tracing/perfetto_task_runner.cc",
@ -2353,6 +2303,8 @@ component("base") {
      sources += [
        "trace_event/etw_interceptor_win.cc",
        "trace_event/etw_interceptor_win.h",
+        "trace_event/trace_event_etw_export_win.cc",
+        "trace_event/trace_event_etw_export_win.h",
        "trace_event/trace_logging_minimal_win.cc",
        "trace_event/trace_logging_minimal_win.h",
      ]
@ -2478,7 +2430,7 @@ buildflag_header("debugging_buildflags") {
 buildflag_header("feature_list_buildflags") {
  header = "feature_list_buildflags.h"

-  if (is_chromeos) {
+  if (is_chromeos_ash) {
    flags = [
      "ENABLE_BANNED_BASE_FEATURE_PREFIX=true",
      "BANNED_BASE_FEATURE_PREFIX=\"CrOSLateBoot\"",
@ -2600,7 +2552,10 @@ static_library("base_static") {
    "immediate_crash.h",
  ]

-  deps = [ ":fuzzing_buildflags" ]
+  deps = [
+    ":fuzzing_buildflags",
+    "//build:chromeos_buildflags",
+  ]

  if (is_win) {
    sources += [
--- a/src/base/DEPS
+++ b/src/base/DEPS
@ -3,7 +3,6 @@ include_rules = [
  "+third_party/apple_apsl",
  "+third_party/boringssl/src/include",
  "+third_party/ced",
-  "+third_party/fuzztest",
  # We are moving the old jni_generator to jni_zero, some references will remain
  # in //base.
  "+third_party/jni_zero",
--- a/src/base/allocator/dispatcher/configuration.h
+++ b/src/base/allocator/dispatcher/configuration.h
@ -21,4 +21,4 @@ constexpr size_t kMaximumNumberOfObservers = 4;

 }  // namespace base::allocator::dispatcher::configuration

-#endif  // BASE_ALLOCATOR_DISPATCHER_CONFIGURATION_H_
+#endif  // BASE_ALLOCATOR_DISPATCHER_CONFIGURATION_H_
--- a/src/base/allocator/dispatcher/dispatcher.cc
+++ b/src/base/allocator/dispatcher/dispatcher.cc
@ -16,7 +16,7 @@
 #endif

 #if PA_BUILDFLAG(USE_PARTITION_ALLOC)
-#include "partition_alloc/partition_alloc_hooks.h"  // nogncheck
+#include "partition_alloc/partition_alloc_hooks.h"
 #endif

 namespace base::allocator::dispatcher {
--- a/src/base/allocator/dispatcher/dispatcher.h
+++ b/src/base/allocator/dispatcher/dispatcher.h
@ -5,11 +5,11 @@
 #ifndef BASE_ALLOCATOR_DISPATCHER_DISPATCHER_H_
 #define BASE_ALLOCATOR_DISPATCHER_DISPATCHER_H_

-#include <memory>
-
 #include "base/allocator/dispatcher/internal/dispatcher_internal.h"
 #include "base/base_export.h"

+#include <memory>
+
 namespace base::allocator::dispatcher {

 namespace internal {
--- a/src/base/allocator/dispatcher/initializer.h
+++ b/src/base/allocator/dispatcher/initializer.h
@ -5,13 +5,13 @@
 #ifndef BASE_ALLOCATOR_DISPATCHER_INITIALIZER_H_
 #define BASE_ALLOCATOR_DISPATCHER_INITIALIZER_H_

-#include <tuple>
-#include <utility>
-
 #include "base/allocator/dispatcher/configuration.h"
 #include "base/allocator/dispatcher/dispatcher.h"
 #include "base/allocator/dispatcher/internal/tools.h"

+#include <tuple>
+#include <utility>
+
 namespace base::allocator::dispatcher {
 namespace internal {

--- a/src/base/allocator/dispatcher/internal/dispatch_data.h
+++ b/src/base/allocator/dispatcher/internal/dispatch_data.h
@ -10,11 +10,11 @@
 #include "partition_alloc/buildflags.h"

 #if PA_BUILDFLAG(USE_PARTITION_ALLOC)
-#include "partition_alloc/partition_alloc_hooks.h"  // nogncheck
+#include "partition_alloc/partition_alloc_hooks.h"
 #endif

 #if PA_BUILDFLAG(USE_ALLOCATOR_SHIM)
-#include "partition_alloc/shim/allocator_shim.h"  // nogncheck
+#include "partition_alloc/shim/allocator_shim.h"
 #endif

 namespace base::allocator::dispatcher::internal {
--- a/src/base/allocator/dispatcher/internal/dispatcher_internal.h
+++ b/src/base/allocator/dispatcher/internal/dispatcher_internal.h
@ -16,7 +16,7 @@
 #include "partition_alloc/buildflags.h"

 #if PA_BUILDFLAG(USE_PARTITION_ALLOC)
-#include "partition_alloc/partition_alloc_allocation_data.h"  // nogncheck
+#include "partition_alloc/partition_alloc_allocation_data.h"
 #endif

 #if PA_BUILDFLAG(USE_ALLOCATOR_SHIM)
--- a/src/base/allocator/dispatcher/subsystem.h
+++ b/src/base/allocator/dispatcher/subsystem.h
@ -24,4 +24,4 @@ enum class AllocationSubsystem {
 };
 }  // namespace base::allocator::dispatcher

-#endif  // BASE_ALLOCATOR_DISPATCHER_SUBSYSTEM_H_
+#endif  // BASE_ALLOCATOR_DISPATCHER_SUBSYSTEM_H_
--- a/src/base/allocator/dispatcher/testing/dispatcher_test.h
+++ b/src/base/allocator/dispatcher/testing/dispatcher_test.h
@ -24,4 +24,4 @@ struct DispatcherTest : public ::testing::Test {

 }  // namespace base::allocator::dispatcher::testing

-#endif  // BASE_ALLOCATOR_DISPATCHER_TESTING_DISPATCHER_TEST_H_
+#endif  // BASE_ALLOCATOR_DISPATCHER_TESTING_DISPATCHER_TEST_H_
--- a/src/base/allocator/dispatcher/testing/observer_mock.h
+++ b/src/base/allocator/dispatcher/testing/observer_mock.h
@ -30,4 +30,4 @@ struct ObserverMock {
 }  // namespace testing
 }  // namespace base::allocator::dispatcher

-#endif  // BASE_ALLOCATOR_DISPATCHER_TESTING_OBSERVER_MOCK_H_
+#endif  // BASE_ALLOCATOR_DISPATCHER_TESTING_OBSERVER_MOCK_H_
--- a/src/base/allocator/dispatcher/tls.cc
+++ b/src/base/allocator/dispatcher/tls.cc
@ -8,14 +8,14 @@

 #if USE_LOCAL_TLS_EMULATION()

-#include <sys/mman.h>
-
 #include "base/check.h"
 #include "base/dcheck_is_on.h"
 #include "base/debug/crash_logging.h"
 #include "base/immediate_crash.h"
 #include "build/build_config.h"

+#include <sys/mman.h>
+
 #if BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_LINUX)
 #include <sys/prctl.h>
 #endif
--- a/src/base/allocator/dispatcher/tls.h
+++ b/src/base/allocator/dispatcher/tls.h
@ -17,21 +17,17 @@
 #endif

 #if USE_LOCAL_TLS_EMULATION()
-#include <pthread.h>
-
 #include <algorithm>
 #include <atomic>
-#include <functional>
 #include <memory>
 #include <mutex>

 #include "base/base_export.h"
 #include "base/check.h"
 #include "base/compiler_specific.h"
+#include "partition_alloc/partition_alloc_constants.h"

-#if PA_BUILDFLAG(USE_PARTITION_ALLOC)
-#include "partition_alloc/partition_alloc_constants.h"  // nogncheck
-#endif
+#include <pthread.h>

 #if HAS_FEATURE(thread_sanitizer)
 #define DISABLE_TSAN_INSTRUMENTATION __attribute__((no_sanitize("thread")))
--- a/src/base/allocator/miracle_parameter.h
+++ b/src/base/allocator/miracle_parameter.h
@ -166,7 +166,7 @@ Enum GetMiracleParameterAsEnum(
                                   default_value, type, options)            \
  type function_name() {                                                    \
    static const type value = miracle_parameter::GetMiracleParameterAsEnum( \
-        feature, param_name, default_value, base::span(options));           \
+        feature, param_name, default_value, base::make_span(options));      \
    return value;                                                           \
  }

--- a/src/base/allocator/partition_alloc_features.cc
+++ b/src/base/allocator/partition_alloc_features.cc
@ -12,6 +12,7 @@
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "build/chromecast_buildflags.h"
+#include "build/chromeos_buildflags.h"
 #include "partition_alloc/buildflags.h"
 #include "partition_alloc/partition_alloc_base/time/time.h"
 #include "partition_alloc/partition_alloc_constants.h"
@ -19,7 +20,8 @@
 #include "partition_alloc/shim/allocator_shim_dispatch_to_noop_on_free.h"
 #include "partition_alloc/thread_cache.h"

-namespace base::features {
+namespace base {
+namespace features {

 namespace {

@ -46,8 +48,7 @@ constexpr FeatureParam<UnretainedDanglingPtrMode>::Option
        {UnretainedDanglingPtrMode::kDumpWithoutCrashing,
         "dump_without_crashing"},
 };
-// Note: Do not use the prepared macro as of no need for a local cache.
-constinit const FeatureParam<UnretainedDanglingPtrMode>
+const base::FeatureParam<UnretainedDanglingPtrMode>
    kUnretainedDanglingPtrModeParam = {
        &kPartitionAllocUnretainedDanglingPtr,
        "mode",
@ -72,8 +73,7 @@ constexpr FeatureParam<DanglingPtrMode>::Option kDanglingPtrModeOption[] = {
    {DanglingPtrMode::kCrash, "crash"},
    {DanglingPtrMode::kLogOnly, "log_only"},
 };
-// Note: Do not use the prepared macro as of no need for a local cache.
-constinit const FeatureParam<DanglingPtrMode> kDanglingPtrModeParam{
+const base::FeatureParam<DanglingPtrMode> kDanglingPtrModeParam{
    &kPartitionAllocDanglingPtr,
    "mode",
    DanglingPtrMode::kCrash,
@ -83,8 +83,7 @@ constexpr FeatureParam<DanglingPtrType>::Option kDanglingPtrTypeOption[] = {
    {DanglingPtrType::kAll, "all"},
    {DanglingPtrType::kCrossTask, "cross_task"},
 };
-// Note: Do not use the prepared macro as of no need for a local cache.
-constinit const FeatureParam<DanglingPtrType> kDanglingPtrTypeParam{
+const base::FeatureParam<DanglingPtrType> kDanglingPtrTypeParam{
    &kPartitionAllocDanglingPtr,
    "type",
    DanglingPtrType::kAll,
@ -110,7 +109,7 @@ MIRACLE_PARAMETER_FOR_INT(

 BASE_FEATURE(kPartitionAllocLargeEmptySlotSpanRing,
             "PartitionAllocLargeEmptySlotSpanRing",
-#if BUILDFLAG(IS_MAC) || BUILDFLAG(IS_WIN)
+#if BUILDFLAG(IS_MAC)
             FEATURE_ENABLED_BY_DEFAULT);
 #else
             FEATURE_DISABLED_BY_DEFAULT);
@ -129,8 +128,7 @@ constexpr FeatureParam<PartitionAllocWithAdvancedChecksEnabledProcesses>::Option
         kNonRendererStr},
        {PartitionAllocWithAdvancedChecksEnabledProcesses::kAllProcesses,
         kAllProcessesStr}};
-// Note: Do not use the prepared macro as of no need for a local cache.
-constinit const FeatureParam<PartitionAllocWithAdvancedChecksEnabledProcesses>
+const base::FeatureParam<PartitionAllocWithAdvancedChecksEnabledProcesses>
    kPartitionAllocWithAdvancedChecksEnabledProcessesParam{
        &kPartitionAllocWithAdvancedChecks, kPAFeatureEnabledProcessesStr,
        PartitionAllocWithAdvancedChecksEnabledProcesses::kBrowserOnly,
@ -140,17 +138,10 @@ BASE_FEATURE(kPartitionAllocSchedulerLoopQuarantine,
             "PartitionAllocSchedulerLoopQuarantine",
             FEATURE_DISABLED_BY_DEFAULT);
 // Scheduler Loop Quarantine's per-branch capacity in bytes.
-// Note: Do not use the prepared macro as of no need for a local cache.
-constinit const FeatureParam<int>
+const base::FeatureParam<int>
    kPartitionAllocSchedulerLoopQuarantineBranchCapacity{
        &kPartitionAllocSchedulerLoopQuarantine,
        "PartitionAllocSchedulerLoopQuarantineBranchCapacity", 0};
-// Scheduler Loop Quarantine's capacity for the UI thread in bytes.
-BASE_FEATURE_PARAM(int,
-                   kPartitionAllocSchedulerLoopQuarantineBrowserUICapacity,
-                   &kPartitionAllocSchedulerLoopQuarantine,
-                   "PartitionAllocSchedulerLoopQuarantineBrowserUICapacity",
-                   0);

 BASE_FEATURE(kPartitionAllocZappingByFreeFlags,
             "PartitionAllocZappingByFreeFlags",
@ -159,10 +150,6 @@ BASE_FEATURE(kPartitionAllocZappingByFreeFlags,
 BASE_FEATURE(kPartitionAllocEventuallyZeroFreedMemory,
             "PartitionAllocEventuallyZeroFreedMemory",
             FEATURE_DISABLED_BY_DEFAULT);
-
-BASE_FEATURE(kPartitionAllocFewerMemoryRegions,
-             "PartitionAllocFewerMemoryRegions",
-             FEATURE_DISABLED_BY_DEFAULT);
 #endif  // PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)

 BASE_FEATURE(kPartitionAllocBackupRefPtr,
@ -182,31 +169,24 @@ constexpr FeatureParam<BackupRefPtrEnabledProcesses>::Option
        {BackupRefPtrEnabledProcesses::kNonRenderer, kNonRendererStr},
        {BackupRefPtrEnabledProcesses::kAllProcesses, kAllProcessesStr}};

-BASE_FEATURE_ENUM_PARAM(BackupRefPtrEnabledProcesses,
-                        kBackupRefPtrEnabledProcessesParam,
-                        &kPartitionAllocBackupRefPtr,
-                        kPAFeatureEnabledProcessesStr,
+const base::FeatureParam<BackupRefPtrEnabledProcesses>
+    kBackupRefPtrEnabledProcessesParam{
+        &kPartitionAllocBackupRefPtr, kPAFeatureEnabledProcessesStr,
 #if PA_BUILDFLAG(IS_MAC) && PA_BUILDFLAG(PA_ARCH_CPU_ARM64)
-                        BackupRefPtrEnabledProcesses::kNonRenderer,
+        BackupRefPtrEnabledProcesses::kNonRenderer,
 #else
-                        BackupRefPtrEnabledProcesses::kAllProcesses,
+        BackupRefPtrEnabledProcesses::kAllProcesses,
 #endif
-                        &kBackupRefPtrEnabledProcessesOptions);
+        &kBackupRefPtrEnabledProcessesOptions};

 constexpr FeatureParam<BackupRefPtrMode>::Option kBackupRefPtrModeOptions[] = {
    {BackupRefPtrMode::kDisabled, "disabled"},
    {BackupRefPtrMode::kEnabled, "enabled"},
 };

-BASE_FEATURE_ENUM_PARAM(BackupRefPtrMode,
-                        kBackupRefPtrModeParam,
-                        &kPartitionAllocBackupRefPtr,
-                        "brp-mode",
-                        BackupRefPtrMode::kEnabled,
-                        &kBackupRefPtrModeOptions);
-// Note: Do not use the prepared macro as of no need for a local cache.
-constinit const FeatureParam<int> kBackupRefPtrExtraExtrasSizeParam{
-    &kPartitionAllocBackupRefPtr, "brp-extra-extras-size", 0};
+const base::FeatureParam<BackupRefPtrMode> kBackupRefPtrModeParam{
+    &kPartitionAllocBackupRefPtr, "brp-mode", BackupRefPtrMode::kEnabled,
+    &kBackupRefPtrModeOptions};

 BASE_FEATURE(kPartitionAllocMemoryTagging,
             "PartitionAllocMemoryTagging",
@ -221,8 +201,7 @@ constexpr FeatureParam<MemtagMode>::Option kMemtagModeOptions[] = {
    {MemtagMode::kSync, "sync"},
    {MemtagMode::kAsync, "async"}};

-// Note: Do not use the prepared macro as of no need for a local cache.
-constinit const FeatureParam<MemtagMode> kMemtagModeParam{
+const base::FeatureParam<MemtagMode> kMemtagModeParam{
    &kPartitionAllocMemoryTagging, "memtag-mode",
 #if PA_BUILDFLAG(USE_FULL_MTE)
    MemtagMode::kSync,
@ -236,8 +215,7 @@ constexpr FeatureParam<RetagMode>::Option kRetagModeOptions[] = {
    {RetagMode::kRandom, "random"},
 };

-// Note: Do not use the prepared macro as of no need for a local cache.
-constinit const FeatureParam<RetagMode> kRetagModeParam{
+const base::FeatureParam<RetagMode> kRetagModeParam{
    &kPartitionAllocMemoryTagging, "retag-mode", RetagMode::kIncrement,
    &kRetagModeOptions};

@ -247,8 +225,7 @@ constexpr FeatureParam<MemoryTaggingEnabledProcesses>::Option
        {MemoryTaggingEnabledProcesses::kNonRenderer, kNonRendererStr},
        {MemoryTaggingEnabledProcesses::kAllProcesses, kAllProcessesStr}};

-// Note: Do not use the prepared macro as of no need for a local cache.
-constinit const FeatureParam<MemoryTaggingEnabledProcesses>
+const base::FeatureParam<MemoryTaggingEnabledProcesses>
    kMemoryTaggingEnabledProcessesParam{
        &kPartitionAllocMemoryTagging, kPAFeatureEnabledProcessesStr,
 #if PA_BUILDFLAG(USE_FULL_MTE)
@ -273,15 +250,13 @@ BASE_FEATURE(kPartitionAllocPermissiveMte,
 #endif
 );

-BASE_FEATURE(kAsanBrpDereferenceCheck,
-             "AsanBrpDereferenceCheck",
-             FEATURE_ENABLED_BY_DEFAULT);
-BASE_FEATURE(kAsanBrpExtractionCheck,
-             "AsanBrpExtractionCheck",      // Not much noise at the moment to
-             FEATURE_DISABLED_BY_DEFAULT);  // enable by default.
-BASE_FEATURE(kAsanBrpInstantiationCheck,
-             "AsanBrpInstantiationCheck",
-             FEATURE_ENABLED_BY_DEFAULT);
+const base::FeatureParam<bool> kBackupRefPtrAsanEnableDereferenceCheckParam{
+    &kPartitionAllocBackupRefPtr, "asan-enable-dereference-check", true};
+const base::FeatureParam<bool> kBackupRefPtrAsanEnableExtractionCheckParam{
+    &kPartitionAllocBackupRefPtr, "asan-enable-extraction-check",
+    false};  // Not much noise at the moment to enable by default.
+const base::FeatureParam<bool> kBackupRefPtrAsanEnableInstantiationCheckParam{
+    &kPartitionAllocBackupRefPtr, "asan-enable-instantiation-check", true};

 // If enabled, switches the bucket distribution to a denser one.
 //
@ -295,31 +270,29 @@ BASE_FEATURE(kPartitionAllocUseDenserDistribution,
             FEATURE_ENABLED_BY_DEFAULT
 #endif  // BUILDFLAG(IS_ANDROID) && defined(ARCH_CPU_32_BITS)
 );
-const FeatureParam<BucketDistributionMode>::Option
+const base::FeatureParam<BucketDistributionMode>::Option
    kPartitionAllocBucketDistributionOption[] = {
        {BucketDistributionMode::kDefault, "default"},
        {BucketDistributionMode::kDenser, "denser"},
 };
-// Note: Do not use the prepared macro as of no need for a local cache.
-constinit const FeatureParam<BucketDistributionMode>
-    kPartitionAllocBucketDistributionParam{
-        &kPartitionAllocUseDenserDistribution, "mode",
+const base::FeatureParam<BucketDistributionMode>
+    kPartitionAllocBucketDistributionParam {
+  &kPartitionAllocUseDenserDistribution, "mode",
 #if BUILDFLAG(IS_ANDROID) && defined(ARCH_CPU_32_BITS)
-        BucketDistributionMode::kDefault,
+      BucketDistributionMode::kDefault,
 #else
-        BucketDistributionMode::kDenser,
+      BucketDistributionMode::kDenser,
 #endif  // BUILDFLAG(IS_ANDROID) && defined(ARCH_CPU_32_BITS)
-        &kPartitionAllocBucketDistributionOption};
+      &kPartitionAllocBucketDistributionOption
+};

 BASE_FEATURE(kPartitionAllocMemoryReclaimer,
             "PartitionAllocMemoryReclaimer",
             FEATURE_ENABLED_BY_DEFAULT);
-BASE_FEATURE_PARAM(TimeDelta,
-                   kPartitionAllocMemoryReclaimerInterval,
-                   &kPartitionAllocMemoryReclaimer,
-                   "interval",
-                   TimeDelta()  // Defaults to zero.
-);
+const base::FeatureParam<TimeDelta> kPartitionAllocMemoryReclaimerInterval = {
+    &kPartitionAllocMemoryReclaimer, "interval",
+    TimeDelta(),  // Defaults to zero.
+};

 // Configures whether we set a lower limit for renderers that do not have a main
 // frame, similar to the limit that is already done for backgrounded renderers.
@ -332,17 +305,16 @@ BASE_FEATURE(kLowerPAMemoryLimitForNonMainRenderers,
 BASE_FEATURE(kPartitionAllocStraightenLargerSlotSpanFreeLists,
             "PartitionAllocStraightenLargerSlotSpanFreeLists",
             FEATURE_ENABLED_BY_DEFAULT);
-const FeatureParam<partition_alloc::StraightenLargerSlotSpanFreeListsMode>::
-    Option kPartitionAllocStraightenLargerSlotSpanFreeListsModeOption[] = {
+const base::FeatureParam<
+    partition_alloc::StraightenLargerSlotSpanFreeListsMode>::Option
+    kPartitionAllocStraightenLargerSlotSpanFreeListsModeOption[] = {
        {partition_alloc::StraightenLargerSlotSpanFreeListsMode::
             kOnlyWhenUnprovisioning,
         "only-when-unprovisioning"},
        {partition_alloc::StraightenLargerSlotSpanFreeListsMode::kAlways,
         "always"},
 };
-// Note: Do not use the prepared macro as of no need for a local cache.
-constinit const FeatureParam<
-    partition_alloc::StraightenLargerSlotSpanFreeListsMode>
+const base::FeatureParam<partition_alloc::StraightenLargerSlotSpanFreeListsMode>
    kPartitionAllocStraightenLargerSlotSpanFreeListsMode = {
        &kPartitionAllocStraightenLargerSlotSpanFreeLists,
        "mode",
@ -375,11 +347,9 @@ BASE_FEATURE(kPageAllocatorRetryOnCommitFailure,
 // The feature: kPartialLowEndModeOnMidRangeDevices is defined in
 // //base/features.cc. Since the following feature param is related to
 // PartitionAlloc, define the param here.
-BASE_FEATURE_PARAM(bool,
-                   kPartialLowEndModeExcludePartitionAllocSupport,
-                   &kPartialLowEndModeOnMidRangeDevices,
-                   "exclude-partition-alloc-support",
-                   false);
+const FeatureParam<bool> kPartialLowEndModeExcludePartitionAllocSupport{
+    &kPartialLowEndModeOnMidRangeDevices, "exclude-partition-alloc-support",
+    false};
 #endif

 BASE_FEATURE(kEnableConfigurableThreadCacheMultiplier,
@ -397,19 +367,19 @@ MIRACLE_PARAMETER_FOR_DOUBLE(GetThreadCacheMultiplierForAndroid,
                             1.)

 constexpr partition_alloc::internal::base::TimeDelta ToPartitionAllocTimeDelta(
-    TimeDelta time_delta) {
+    base::TimeDelta time_delta) {
  return partition_alloc::internal::base::Microseconds(
      time_delta.InMicroseconds());
 }

-constexpr TimeDelta FromPartitionAllocTimeDelta(
+constexpr base::TimeDelta FromPartitionAllocTimeDelta(
    partition_alloc::internal::base::TimeDelta time_delta) {
-  return Microseconds(time_delta.InMicroseconds());
+  return base::Microseconds(time_delta.InMicroseconds());
 }

 BASE_FEATURE(kEnableConfigurableThreadCachePurgeInterval,
             "EnableConfigurableThreadCachePurgeInterval",
-             FEATURE_DISABLED_BY_DEFAULT);
+             base::FEATURE_DISABLED_BY_DEFAULT);

 MIRACLE_PARAMETER_FOR_TIME_DELTA(
    GetThreadCacheMinPurgeIntervalValue,
@ -446,7 +416,7 @@ GetThreadCacheDefaultPurgeInterval() {

 BASE_FEATURE(kEnableConfigurableThreadCacheMinCachedMemoryForPurging,
             "EnableConfigurableThreadCacheMinCachedMemoryForPurging",
-             FEATURE_DISABLED_BY_DEFAULT);
+             base::FEATURE_DISABLED_BY_DEFAULT);

 MIRACLE_PARAMETER_FOR_INT(
    GetThreadCacheMinCachedMemoryForPurgingBytes,
@ -466,9 +436,15 @@ BASE_FEATURE(kPartitionAllocDisableBRPInBufferPartition,
             "PartitionAllocDisableBRPInBufferPartition",
             FEATURE_DISABLED_BY_DEFAULT);

+#if PA_BUILDFLAG(USE_FREELIST_DISPATCHER)
+BASE_FEATURE(kUsePoolOffsetFreelists,
+             "PartitionAllocUsePoolOffsetFreelists",
+             base::FEATURE_DISABLED_BY_DEFAULT);
+#endif
+
 BASE_FEATURE(kPartitionAllocAdjustSizeWhenInForeground,
             "PartitionAllocAdjustSizeWhenInForeground",
-#if BUILDFLAG(IS_MAC) || BUILDFLAG(IS_WIN)
+#if BUILDFLAG(IS_MAC)
             FEATURE_ENABLED_BY_DEFAULT);
 #else
             FEATURE_DISABLED_BY_DEFAULT);
@ -476,12 +452,12 @@ BASE_FEATURE(kPartitionAllocAdjustSizeWhenInForeground,

 BASE_FEATURE(kPartitionAllocUseSmallSingleSlotSpans,
             "PartitionAllocUseSmallSingleSlotSpans",
-             FEATURE_ENABLED_BY_DEFAULT);
+             base::FEATURE_DISABLED_BY_DEFAULT);

 #if PA_CONFIG(ENABLE_SHADOW_METADATA)
 BASE_FEATURE(kPartitionAllocShadowMetadata,
             "PartitionAllocShadowMetadata",
-             FEATURE_DISABLED_BY_DEFAULT);
+             base::FEATURE_DISABLED_BY_DEFAULT);

 constexpr FeatureParam<ShadowMetadataEnabledProcesses>::Option
    kShadowMetadataEnabledProcessesOptions[] = {
@ -489,12 +465,12 @@ constexpr FeatureParam<ShadowMetadataEnabledProcesses>::Option
        {ShadowMetadataEnabledProcesses::kAllChildProcesses,
         kAllChildProcessesStr}};

-// Note: Do not use the prepared macro as of no need for a local cache.
-constinit const FeatureParam<ShadowMetadataEnabledProcesses>
+const base::FeatureParam<ShadowMetadataEnabledProcesses>
    kShadowMetadataEnabledProcessesParam{
        &kPartitionAllocShadowMetadata, kPAFeatureEnabledProcessesStr,
        ShadowMetadataEnabledProcesses::kRendererOnly,
        &kShadowMetadataEnabledProcessesOptions};
 #endif  // PA_CONFIG(ENABLE_SHADOW_METADATA)

-}  // namespace base::features
+}  // namespace features
+}  // namespace base
--- a/src/base/allocator/partition_alloc_features.h
+++ b/src/base/allocator/partition_alloc_features.h
@ -15,7 +15,8 @@
 #include "partition_alloc/partition_alloc_base/time/time.h"
 #include "partition_alloc/partition_root.h"

-namespace base::features {
+namespace base {
+namespace features {

 namespace internal {

@ -36,13 +37,13 @@ enum class PAFeatureEnabledProcesses {

 }  // namespace internal

-BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocUnretainedDanglingPtr);
+extern const BASE_EXPORT Feature kPartitionAllocUnretainedDanglingPtr;
 enum class UnretainedDanglingPtrMode {
  kCrash,
  kDumpWithoutCrashing,
 };
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(UnretainedDanglingPtrMode,
-                                       kUnretainedDanglingPtrModeParam);
+extern const BASE_EXPORT base::FeatureParam<UnretainedDanglingPtrMode>
+    kUnretainedDanglingPtrModeParam;

 // See /docs/dangling_ptr.md
 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocDanglingPtr);
@ -61,7 +62,8 @@ enum class DanglingPtrMode {

  // Note: This will be extended with a single shot DumpWithoutCrashing.
 };
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(DanglingPtrMode, kDanglingPtrModeParam);
+extern const BASE_EXPORT base::FeatureParam<DanglingPtrMode>
+    kDanglingPtrModeParam;
 enum class DanglingPtrType {
  // Act on any dangling raw_ptr released after being freed.
  kAll,  // (default)
@ -72,7 +74,8 @@ enum class DanglingPtrType {

  // Note: This will be extended with LongLived
 };
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(DanglingPtrType, kDanglingPtrTypeParam);
+extern const BASE_EXPORT base::FeatureParam<DanglingPtrType>
+    kDanglingPtrTypeParam;

 using PartitionAllocWithAdvancedChecksEnabledProcesses =
    internal::PAFeatureEnabledProcesses;
@ -85,19 +88,13 @@ BASE_EXPORT int GetPartitionAllocLargeThreadCacheSizeValueForLowRAMAndroid();
 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocLargeEmptySlotSpanRing);

 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocWithAdvancedChecks);
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(
-    PartitionAllocWithAdvancedChecksEnabledProcesses,
-    kPartitionAllocWithAdvancedChecksEnabledProcessesParam);
+extern const BASE_EXPORT
+    base::FeatureParam<PartitionAllocWithAdvancedChecksEnabledProcesses>
+        kPartitionAllocWithAdvancedChecksEnabledProcessesParam;
 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocSchedulerLoopQuarantine);
 // Scheduler Loop Quarantine's per-thread capacity in bytes.
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(
-    int,
-    kPartitionAllocSchedulerLoopQuarantineBranchCapacity);
-// Scheduler Loop Quarantine's capacity for the UI thread in bytes.
-// TODO(https://crbug.com/387470567): Support more thread types.
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(
-    int,
-    kPartitionAllocSchedulerLoopQuarantineBrowserUICapacity);
+extern const BASE_EXPORT base::FeatureParam<int>
+    kPartitionAllocSchedulerLoopQuarantineBranchCapacity;

 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocZappingByFreeFlags);

@ -105,11 +102,6 @@ BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocZappingByFreeFlags);
 // security guarantee, but to increase the compression ratio of PartitionAlloc's
 // fragmented super pages.
 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocEventuallyZeroFreedMemory);
-
-// Whether to make PartitionAlloc use fewer memory regions. This matters on
-// Linux-based systems, where there is a per-process limit that we hit in some
-// cases. See the comment in PartitionBucket::SlotSpanCOmmitedSize() for detail.
-BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocFewerMemoryRegions);
 #endif  // PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)

 using BackupRefPtrEnabledProcesses = internal::PAFeatureEnabledProcesses;
@ -147,38 +139,39 @@ enum class BucketDistributionMode : uint8_t {
 };

 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocBackupRefPtr);
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(BackupRefPtrEnabledProcesses,
-                                       kBackupRefPtrEnabledProcessesParam);
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(BackupRefPtrMode,
-                                       kBackupRefPtrModeParam);
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(int,
-                                       kBackupRefPtrExtraExtrasSizeParam);
+extern const BASE_EXPORT base::FeatureParam<BackupRefPtrEnabledProcesses>
+    kBackupRefPtrEnabledProcessesParam;
+extern const BASE_EXPORT base::FeatureParam<BackupRefPtrMode>
+    kBackupRefPtrModeParam;
 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocMemoryTagging);
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(MemtagMode, kMemtagModeParam);
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(RetagMode, kRetagModeParam);
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(MemoryTaggingEnabledProcesses,
-                                       kMemoryTaggingEnabledProcessesParam);
+extern const BASE_EXPORT base::FeatureParam<MemtagMode> kMemtagModeParam;
+extern const BASE_EXPORT base::FeatureParam<RetagMode> kRetagModeParam;
+extern const BASE_EXPORT base::FeatureParam<MemoryTaggingEnabledProcesses>
+    kMemoryTaggingEnabledProcessesParam;
 // Kill switch for memory tagging. Skips any code related to memory tagging when
 // enabled.
 BASE_EXPORT BASE_DECLARE_FEATURE(kKillPartitionAllocMemoryTagging);
 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocPermissiveMte);
-BASE_EXPORT BASE_DECLARE_FEATURE(kAsanBrpDereferenceCheck);
-BASE_EXPORT BASE_DECLARE_FEATURE(kAsanBrpExtractionCheck);
-BASE_EXPORT BASE_DECLARE_FEATURE(kAsanBrpInstantiationCheck);
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(BucketDistributionMode,
-                                       kPartitionAllocBucketDistributionParam);
+extern const BASE_EXPORT base::FeatureParam<bool>
+    kBackupRefPtrAsanEnableDereferenceCheckParam;
+extern const BASE_EXPORT base::FeatureParam<bool>
+    kBackupRefPtrAsanEnableExtractionCheckParam;
+extern const BASE_EXPORT base::FeatureParam<bool>
+    kBackupRefPtrAsanEnableInstantiationCheckParam;
+extern const BASE_EXPORT base::FeatureParam<BucketDistributionMode>
+    kPartitionAllocBucketDistributionParam;

 BASE_EXPORT BASE_DECLARE_FEATURE(kLowerPAMemoryLimitForNonMainRenderers);
 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocUseDenserDistribution);

 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocMemoryReclaimer);
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(TimeDelta,
-                                       kPartitionAllocMemoryReclaimerInterval);
+extern const BASE_EXPORT base::FeatureParam<TimeDelta>
+    kPartitionAllocMemoryReclaimerInterval;
 BASE_EXPORT BASE_DECLARE_FEATURE(
    kPartitionAllocStraightenLargerSlotSpanFreeLists);
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(
-    partition_alloc::StraightenLargerSlotSpanFreeListsMode,
-    kPartitionAllocStraightenLargerSlotSpanFreeListsMode);
+extern const BASE_EXPORT
+    base::FeatureParam<partition_alloc::StraightenLargerSlotSpanFreeListsMode>
+        kPartitionAllocStraightenLargerSlotSpanFreeListsMode;
 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocSortSmallerSlotSpanFreeLists);
 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocSortActiveSlotSpans);

@ -187,9 +180,8 @@ BASE_EXPORT BASE_DECLARE_FEATURE(kPageAllocatorRetryOnCommitFailure);
 #endif

 #if BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_CHROMEOS)
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(
-    bool,
-    kPartialLowEndModeExcludePartitionAllocSupport);
+extern const base::FeatureParam<bool>
+    kPartialLowEndModeExcludePartitionAllocSupport;
 #endif

 BASE_EXPORT BASE_DECLARE_FEATURE(kEnableConfigurableThreadCacheMultiplier);
@ -210,6 +202,13 @@ BASE_EXPORT int GetThreadCacheMinCachedMemoryForPurgingBytes();

 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocDisableBRPInBufferPartition);

+// This feature is additionally gated behind a buildflag because
+// pool offset freelists cannot be represented when PartitionAlloc uses
+// 32-bit pointers.
+#if PA_BUILDFLAG(USE_FREELIST_DISPATCHER)
+BASE_EXPORT BASE_DECLARE_FEATURE(kUsePoolOffsetFreelists);
+#endif
+
 // When set, partitions use a larger ring buffer and free memory less
 // aggressively when in the foreground.
 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocAdjustSizeWhenInForeground);
@ -224,10 +223,11 @@ BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocUseSmallSingleSlotSpans);
 using ShadowMetadataEnabledProcesses = internal::PAFeatureEnabledProcesses;

 BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocShadowMetadata);
-BASE_EXPORT BASE_DECLARE_FEATURE_PARAM(ShadowMetadataEnabledProcesses,
-                                       kShadowMetadataEnabledProcessesParam);
+extern const BASE_EXPORT base::FeatureParam<ShadowMetadataEnabledProcesses>
+    kShadowMetadataEnabledProcessesParam;
 #endif  // PA_CONFIG(ENABLE_SHADOW_METADATA)

-}  // namespace base::features
+}  // namespace features
+}  // namespace base

 #endif  // BASE_ALLOCATOR_PARTITION_ALLOC_FEATURES_H_
--- a/src/base/allocator/partition_alloc_support.cc
+++ b/src/base/allocator/partition_alloc_support.cc
@ -4,7 +4,6 @@

 #include "base/allocator/partition_alloc_support.h"

-#include <algorithm>
 #include <array>
 #include <cinttypes>
 #include <cstdint>
@ -32,6 +31,7 @@
 #include "base/metrics/histogram_macros.h"
 #include "base/no_destructor.h"
 #include "base/pending_task.h"
+#include "base/ranges/algorithm.h"
 #include "base/strings/string_split.h"
 #include "base/strings/stringprintf.h"
 #include "base/system/sys_info.h"
@ -48,7 +48,6 @@
 #include "partition_alloc/memory_reclaimer.h"
 #include "partition_alloc/page_allocator.h"
 #include "partition_alloc/partition_alloc_base/debug/alias.h"
-#include "partition_alloc/partition_alloc_base/immediate_crash.h"
 #include "partition_alloc/partition_alloc_base/threading/platform_thread.h"
 #include "partition_alloc/partition_alloc_check.h"
 #include "partition_alloc/partition_alloc_config.h"
@ -107,9 +106,12 @@ BootloaderOverride GetBootloaderOverride() {
 }
 #endif

-// Avoid running periodic purging or reclaim for the first minute after the
-// first attempt. This is based on the insight that processes often don't live
-// paste this minute.
+// When under this experiment avoid running periodic purging or reclaim for the
+// first minute after the first attempt. This is based on the insight that
+// processes often don't live paste this minute.
+static BASE_FEATURE(kDelayFirstPeriodicPAPurgeOrReclaim,
+                    "DelayFirstPeriodicPAPurgeOrReclaim",
+                    base::FEATURE_ENABLED_BY_DEFAULT);
 constexpr base::TimeDelta kFirstPAPurgeOrReclaimDelay = base::Minutes(1);

 // This is defined in content/public/common/content_switches.h, which is not
@ -168,8 +170,6 @@ void MemoryReclaimerSupport::Start(scoped_refptr<TaskRunner> task_runner) {
    return;
  }

-  task_runner_ = task_runner;
-
  // The caller of the API fully controls where running the reclaim.
  // However there are a few reasons to recommend that the caller runs
  // it on the main thread:
@ -185,7 +185,13 @@ void MemoryReclaimerSupport::Start(scoped_refptr<TaskRunner> task_runner) {
  // seconds is useful. Since this is meant to run during idle time only, it is
  // a reasonable starting point balancing effectivenes vs cost. See
  // crbug.com/942512 for details and experimental results.
-  MaybeScheduleTask(kFirstPAPurgeOrReclaimDelay);
+  TimeDelta delay;
+  if (base::FeatureList::IsEnabled(kDelayFirstPeriodicPAPurgeOrReclaim)) {
+    delay = std::max(delay, kFirstPAPurgeOrReclaimDelay);
+  }
+
+  task_runner_ = task_runner;
+  MaybeScheduleTask(delay);
 }

 void MemoryReclaimerSupport::SetForegrounded(bool in_foreground) {
@ -246,9 +252,12 @@ void MemoryReclaimerSupport::MaybeScheduleTask(TimeDelta delay) {

 void StartThreadCachePeriodicPurge() {
  auto& instance = ::partition_alloc::ThreadCacheRegistry::Instance();
-  TimeDelta delay = std::max(
-      Microseconds(instance.GetPeriodicPurgeNextIntervalInMicroseconds()),
-      kFirstPAPurgeOrReclaimDelay);
+  TimeDelta delay =
+      Microseconds(instance.GetPeriodicPurgeNextIntervalInMicroseconds());
+
+  if (base::FeatureList::IsEnabled(kDelayFirstPeriodicPAPurgeOrReclaim)) {
+    delay = std::max(delay, kFirstPAPurgeOrReclaimDelay);
+  }

  SingleThreadTaskRunner::GetCurrentDefault()->PostDelayedTask(
      FROM_HERE, BindOnce(RunThreadCachePeriodicPurge), delay);
@ -455,7 +464,7 @@ std::string ExtractDanglingPtrSignature(std::string stacktrace) {
  size_t caller_index = 0;
  for (size_t i = 0; i < lines.size(); ++i) {
    for (const auto& patterns : callee_patterns) {
-      if (std::ranges::all_of(patterns, [&](std::string_view pattern) {
+      if (ranges::all_of(patterns, [&](std::string_view pattern) {
            return lines[i].find(pattern) != std::string_view::npos;
          })) {
        caller_index = i + 1;
@ -578,55 +587,38 @@ void DanglingRawPtrReleased(uintptr_t id) {

  std::string dangling_signature = ExtractDanglingPtrSignature(
      free_info, stack_trace_release, task_trace_release);
-
-  {
-    // Log the full error in a single LogMessage. Printing StackTrace is
-    // expensive, so we want to avoid interleaving the output with other logs.
-    logging::LogMessage log_message(__FILE__, __LINE__, logging::LOGGING_ERROR);
-    std::ostream& error = log_message.stream();
-
-    // The dangling signature can be used by script to locate the origin of
-    // every dangling pointers.
-    error << "\n\n"
-          << ExtractDanglingPtrSignature(free_info, stack_trace_release,
-                                         task_trace_release)
-          << "\n\n";
-
-    error << "[DanglingPtr](1/3) A raw_ptr/raw_ref is dangling.\n\n";
-
-    auto print_traces = [](debug::StackTrace stack_trace,
-                           debug::TaskTrace task_trace, std::ostream& error) {
-      error << "Stack trace:\n";
-      error << stack_trace << "\n";
-
-      // Printing "Task trace:" is implied by the TaskTrace itself.
-      if (!task_trace.empty()) {
-        error << task_trace << "\n";
-      }
-    };
-
-    error << "[DanglingPtr](2/3) ";
-    if (free_info) {
-      error << "First, the memory was freed at:\n\n";
-      print_traces(free_info->stack_trace, free_info->task_trace, error);
-    } else {
-      error << "It was not recorded where the memory was freed.\n";
-    }
-
-    error << "[DanglingPtr](3/3) Later, the dangling raw_ptr was released "
-             "at:\n\n";
-    print_traces(stack_trace_release, task_trace_release, error);
-
-    error << "Please check for more information on:\n";
-    error << "https://chromium.googlesource.com/chromium/src/+/main/docs/";
-    error << "dangling_ptr_guide.md\n";
-    error << "\n";
+  static const char dangling_ptr_footer[] =
+      "\n"
+      "\n"
+      "Please check for more information on:\n"
+      "https://chromium.googlesource.com/chromium/src/+/main/docs/"
+      "dangling_ptr_guide.md\n"
+      "\n"
+      "Googlers: Please give us your feedback about the dangling pointer\n"
+      "          detector at:\n"
+      "          http://go/dangling-ptr-cq-survey\n";
+  if (free_info) {
+    LOG(ERROR) << "Detected dangling raw_ptr with id="
+               << StringPrintf("0x%016" PRIxPTR, id) << ":\n"
+               << dangling_signature << "\n\n"
+               << "The memory was freed at:\n"
+               << free_info->stack_trace << "\n"
+               << free_info->task_trace << "\n"
+               << "The dangling raw_ptr was released at:\n"
+               << stack_trace_release << "\n"
+               << task_trace_release << dangling_ptr_footer;
+  } else {
+    LOG(ERROR) << "Detected dangling raw_ptr with id="
+               << StringPrintf("0x%016" PRIxPTR, id) << ":\n\n"
+               << dangling_signature << "\n\n"
+               << "It was not recorded where the memory was freed.\n\n"
+               << "The dangling raw_ptr was released at:\n"
+               << stack_trace_release << "\n"
+               << task_trace_release << dangling_ptr_footer;
  }

  if constexpr (dangling_pointer_mode == features::DanglingPtrMode::kCrash) {
-    // We use `PA_IMMEDIATE_CRASH()` instead of base's ImmediateCrash() to avoid
-    // printing the raw_ptr release stack trace twice.
-    PA_IMMEDIATE_CRASH();
+    ImmediateCrash();
  }
 }

@ -657,16 +649,16 @@ void CheckDanglingRawPtrBufferEmpty() {
    std::vector<std::array<const void*, 32>> stack_traces =
        internal::InstanceTracer::GetStackTracesForDanglingRefs(entry->id);
    for (const auto& raw_stack_trace : stack_traces) {
-      CHECK(std::ranges::is_partitioned(raw_stack_trace, is_frame_ptr_not_null))
+      CHECK(ranges::is_partitioned(raw_stack_trace, is_frame_ptr_not_null))
          << "`raw_stack_trace` is expected to be partitioned: non-null values "
             "at the begining followed by `nullptr`s.";
      LOG(ERROR) << "Dangling reference from:\n";
      LOG(ERROR) << debug::StackTrace(
                        // This call truncates the `nullptr` tail of the stack
                        // trace (see the `is_partitioned` CHECK above).
-                        span(raw_stack_trace.begin(),
-                             std::ranges::partition_point(
-                                 raw_stack_trace, is_frame_ptr_not_null)))
+                        make_span(raw_stack_trace.begin(),
+                                  ranges::partition_point(
+                                      raw_stack_trace, is_frame_ptr_not_null)))
                 << "\n";
    }
 #else
@ -870,28 +862,36 @@ PartitionAllocSupport::GetBrpConfiguration(const std::string& process_type) {
  // TODO(bartekn): Switch to DCHECK once confirmed there are no issues.
  CHECK(base::FeatureList::GetInstance());

-#if PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC) && \
-    PA_BUILDFLAG(ENABLE_BACKUP_REF_PTR_SUPPORT) && \
-    !PA_BUILDFLAG(FORCE_DISABLE_BACKUP_REF_PTR_FEATURE)
-
+  bool process_affected_by_brp_flag = false;
+#if (PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC) &&          \
+     PA_BUILDFLAG(ENABLE_BACKUP_REF_PTR_SUPPORT) &&          \
+     !PA_BUILDFLAG(FORCE_DISABLE_BACKUP_REF_PTR_FEATURE)) || \
+    PA_BUILDFLAG(USE_ASAN_BACKUP_REF_PTR)
  if (base::FeatureList::IsEnabled(
-          base::features::kPartitionAllocBackupRefPtr) &&
-      base::features::kBackupRefPtrModeParam.Get() !=
-          base::features::BackupRefPtrMode::kDisabled &&
-      ShouldEnableFeatureOnProcess(
-          base::features::kBackupRefPtrEnabledProcessesParam.Get(),
-          process_type)) {
-    return {
-        .enable_brp = true,
-        .extra_extras_size = static_cast<size_t>(
-            base::features::kBackupRefPtrExtraExtrasSizeParam.Get()),
-    };
+          base::features::kPartitionAllocBackupRefPtr)) {
+    // No specified process type means this is the Browser process.
+    process_affected_by_brp_flag = ShouldEnableFeatureOnProcess(
+        base::features::kBackupRefPtrEnabledProcessesParam.Get(), process_type);
  }
+#endif  // (PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC) &&
+        // PA_BUILDFLAG(ENABLE_BACKUP_REF_PTR_SUPPORT)&&
+        // !PA_BUILDFLAG(FORCE_DISABLE_BACKUP_REF_PTR_FEATURE)) ||
+        // PA_BUILDFLAG(USE_ASAN_BACKUP_REF_PTR)
+
+  const bool enable_brp =
+#if PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC) && \
+    PA_BUILDFLAG(ENABLE_BACKUP_REF_PTR_SUPPORT)
+      // kDisabled is equivalent to !IsEnabled(kPartitionAllocBackupRefPtr).
+      process_affected_by_brp_flag &&
+      base::features::kBackupRefPtrModeParam.Get() !=
+          base::features::BackupRefPtrMode::kDisabled;
+#else
+      false;
 #endif

  return {
-      .enable_brp = false,
-      .extra_extras_size = 0,
+      enable_brp,
+      process_affected_by_brp_flag,
  };
 }

@ -994,26 +994,20 @@ void PartitionAllocSupport::ReconfigureAfterFeatureListInit(
  [[maybe_unused]] BrpConfiguration brp_config =
      GetBrpConfiguration(process_type);

-  // Configure ASAN hooks to report the `MiraclePtr status`. This is enabled
-  // only if BackupRefPtr is normally enabled in the current process for the
-  // current platform. Note that CastOS and iOS aren't protected by BackupRefPtr
-  // a the moment, so they are excluded.
-#if PA_BUILDFLAG(USE_ASAN_BACKUP_REF_PTR) && !PA_BUILDFLAG(IS_CASTOS) && \
-    !PA_BUILDFLAG(IS_IOS)
-  if (ShouldEnableFeatureOnProcess(
-          base::features::kBackupRefPtrEnabledProcessesParam.Get(),
-          process_type)) {
-    RawPtrAsanService::GetInstance().Configure(
-        EnableDereferenceCheck(
-            FeatureList::IsEnabled(features::kAsanBrpDereferenceCheck)),
-        EnableExtractionCheck(
-            FeatureList::IsEnabled(features::kAsanBrpExtractionCheck)),
-        EnableInstantiationCheck(
-            FeatureList::IsEnabled(features::kAsanBrpInstantiationCheck)));
+#if PA_BUILDFLAG(USE_ASAN_BACKUP_REF_PTR)
+  if (brp_config.process_affected_by_brp_flag) {
+    base::RawPtrAsanService::GetInstance().Configure(
+        base::EnableDereferenceCheck(
+            base::features::kBackupRefPtrAsanEnableDereferenceCheckParam.Get()),
+        base::EnableExtractionCheck(
+            base::features::kBackupRefPtrAsanEnableExtractionCheckParam.Get()),
+        base::EnableInstantiationCheck(
+            base::features::kBackupRefPtrAsanEnableInstantiationCheckParam
+                .Get()));
  } else {
-    RawPtrAsanService::GetInstance().Configure(EnableDereferenceCheck(false),
-                                               EnableExtractionCheck(false),
-                                               EnableInstantiationCheck(false));
+    base::RawPtrAsanService::GetInstance().Configure(
+        base::EnableDereferenceCheck(false), base::EnableExtractionCheck(false),
+        base::EnableInstantiationCheck(false));
  }
 #endif  // PA_BUILDFLAG(USE_ASAN_BACKUP_REF_PTR)

@ -1040,8 +1034,13 @@ void PartitionAllocSupport::ReconfigureAfterFeatureListInit(
      base::features::kPartitionAllocZappingByFreeFlags);
  const bool eventually_zero_freed_memory = base::FeatureList::IsEnabled(
      base::features::kPartitionAllocEventuallyZeroFreedMemory);
-  const bool fewer_memory_regions = base::FeatureList::IsEnabled(
-      base::features::kPartitionAllocFewerMemoryRegions);
+
+#if PA_BUILDFLAG(USE_FREELIST_DISPATCHER)
+  const bool use_pool_offset_freelists =
+      base::FeatureList::IsEnabled(base::features::kUsePoolOffsetFreelists);
+#else
+  const bool use_pool_offset_freelists = false;
+#endif  // PA_BUILDFLAG(USE_FREELIST_DISPATCHER)

  bool enable_memory_tagging = false;
  partition_alloc::TagViolationReportingMode memory_tagging_reporting_mode =
@ -1137,14 +1136,13 @@ void PartitionAllocSupport::ReconfigureAfterFeatureListInit(

  allocator_shim::ConfigurePartitions(
      allocator_shim::EnableBrp(brp_config.enable_brp),
-      brp_config.extra_extras_size,
      allocator_shim::EnableMemoryTagging(enable_memory_tagging),
      memory_tagging_reporting_mode, bucket_distribution,
      allocator_shim::SchedulerLoopQuarantine(scheduler_loop_quarantine),
      scheduler_loop_quarantine_branch_capacity_in_bytes,
      allocator_shim::ZappingByFreeFlags(zapping_by_free_flags),
      allocator_shim::EventuallyZeroFreedMemory(eventually_zero_freed_memory),
-      allocator_shim::FewerMemoryRegions(fewer_memory_regions),
+      allocator_shim::UsePoolOffsetFreelists(use_pool_offset_freelists),
      use_small_single_slot_spans);

  const uint32_t extras_size = allocator_shim::GetMainPartitionRootExtrasSize();
@ -1170,18 +1168,6 @@ void PartitionAllocSupport::ReconfigureAfterFeatureListInit(
        ->EnableLargeEmptySlotSpanRing();
  }

-  if (process_type == "" &&
-      base::FeatureList::IsEnabled(
-          base::features::kPartitionAllocSchedulerLoopQuarantine)) {
-    // `ReconfigureAfterTaskRunnerInit()` is called on the UI thread.
-    const size_t capacity_in_bytes = static_cast<size_t>(
-        base::features::kPartitionAllocSchedulerLoopQuarantineBrowserUICapacity
-            .Get());
-    allocator_shim::internal::PartitionAllocMalloc::Allocator()
-        ->SetSchedulerLoopQuarantineThreadLocalBranchCapacity(
-            capacity_in_bytes);
-  }
-
 #if PA_BUILDFLAG( \
    ENABLE_ALLOCATOR_SHIM_PARTITION_ALLOC_DISPATCH_WITH_ADVANCED_CHECKS_SUPPORT)
  bool enable_pa_with_advanced_checks =
@ -1307,8 +1293,7 @@ void PartitionAllocSupport::ReconfigureAfterTaskRunnerInit(
  if (ShouldEnableShadowMetadata(process_type)) {
    partition_alloc::PartitionRoot::EnableShadowMetadata(
        partition_alloc::internal::PoolHandleMask::kRegular |
-        partition_alloc::internal::PoolHandleMask::kBRP |
-        partition_alloc::internal::PoolHandleMask::kConfigurable);
+        partition_alloc::internal::PoolHandleMask::kBRP);
  }
 #endif  // PA_CONFIG(ENABLE_SHADOW_METADATA)
 }
--- a/src/base/allocator/partition_alloc_support.h
+++ b/src/base/allocator/partition_alloc_support.h
@ -49,9 +49,7 @@ class BASE_EXPORT PartitionAllocSupport {
 public:
  struct BrpConfiguration {
    bool enable_brp = false;
-
-    // TODO(https://crbug.com/371135823): Remove after the investigation.
-    size_t extra_extras_size = 0;
+    bool process_affected_by_brp_flag = false;
  };

  // Reconfigure* functions re-configure PartitionAlloc. It is impossible to
--- a/src/base/allocator/partition_allocator/BUILD.gn
+++ b/src/base/allocator/partition_allocator/BUILD.gn
@ -11,14 +11,8 @@ group("buildflags") {
  public_deps = [ "src/partition_alloc:buildflags" ]
 }

-if (use_partition_alloc && is_clang_or_gcc) {
+if (is_clang_or_gcc) {
  group("partition_alloc") {
    public_deps = [ "src/partition_alloc:partition_alloc" ]
  }
 }
-
-if (use_allocator_shim) {
-  group("allocator_shim") {
-    public_deps = [ "src/partition_alloc:allocator_shim" ]
-  }
-}
--- a/src/base/allocator/partition_allocator/PRESUBMIT.py
+++ b/src/base/allocator/partition_allocator/PRESUBMIT.py
@ -230,20 +230,3 @@ def CheckCpp17CompatibleKeywords(input_api, output_api):
                        '%s:%d\nPartitionAlloc disallows C++20 keywords: %s'
                        % (f.LocalPath(), line_number + 1, keyword)))
    return errors
-
-# Check `NDEBUG` is not used inside partition_alloc. We prefer to use the
-# buildflags `#if PA_BUILDFLAG(IS_DEBUG)` instead.
-def CheckNoNDebug(input_api, output_api):
-    sources = lambda affected_file: input_api.FilterSourceFile(
-        affected_file,
-        files_to_skip=[],
-        files_to_check=[_SOURCE_FILE_PATTERN])
-
-    errors = []
-    for f in input_api.AffectedSourceFiles(sources):
-        for line_number, line in f.ChangedContents():
-            if 'NDEBUG' in line:
-                errors.append(output_api.PresubmitError('%s:%d\nPartitionAlloc'
-                  % (f.LocalPath(), line_number + 1)
-                  + 'disallows NDEBUG, use PA_BUILDFLAG(IS_DEBUG) instead'))
-    return errors
--- a/src/base/allocator/partition_allocator/gn/BUILDCONFIG.gn
+++ b/src/base/allocator/partition_allocator/gn/BUILDCONFIG.gn
@ -52,6 +52,7 @@ is_nacl = false
 is_win = current_os == "win" || current_os == "winuwp"
 is_cast_android = false
 is_castos = false
+is_chromeos_ash = false
 is_cronet_build = false
 enable_expensive_dchecks = false
 dcheck_is_configurable = false
--- a/src/base/allocator/partition_allocator/partition_alloc.gni
+++ b/src/base/allocator/partition_allocator/partition_alloc.gni
@ -4,56 +4,6 @@

 import("//build_overrides/partition_alloc.gni")

-# -----------------------------------------------------------------------------
-# Note on the use of `xxx_default` variable in partition_alloc.
-#
-# GN provides default_args() instruction. It is meant to be used by embedders,
-# to override the default args declared by the embeddees (e.g. partition_alloc).
-# This is the intended way to use GN. It properly interacts with the args.gn
-# user's file.
-#
-# Unfortunately, Chrome and others embedders aren't using it. Instead, they
-# expect embeddees to import global '.gni' file from the embedder, e.g.
-# `//build_overrides/partition_alloc.gni`. This file sets some `xxx_default`
-# variable that will be transferred to the declared args. For instance
-# a library would use:
-# ```
-#     import("//build_overrides/library.gni")
-#     declare_args() {
-#       xxx = xxx_default
-#     }
-# ```
-#
-# We don't really want to break embedders when introducing new args. Ideally,
-# We would have liked to have defaults for default variables. That would be
-# a recursive problem. To resolve it, we sometimes use the `defined(...)`
-# instruction to check if the embedder has defined the `xxx_default` variable or
-# not.
-#
-# In general, we should aim to support the embedders that are using GN normally,
-# and avoid requiring them to define `xxx_default` in the `//build_overrides`
-# -----------------------------------------------------------------------------
-
-# Some embedders uses `is_debug`, it can be used to set the default value of
-# `partition_alloc_is_debug_default`.
-if (!defined(partition_alloc_is_debug_default)) {
-  if (defined(is_debug)) {
-    partition_alloc_is_debug_default = is_debug
-  } else {
-    partition_alloc_is_debug_default = false
-  }
-}
-
-# Some embedders uses `dcheck_always_on`, it can be used to set the default
-# value of `partition_alloc_dcheck_always_on_default`.
-if (!defined(partition_alloc_dcheck_always_on_default)) {
-  if (defined(dcheck_always_on)) {
-    partition_alloc_dcheck_always_on_default = dcheck_always_on
-  } else {
-    partition_alloc_dcheck_always_on_default = false
-  }
-}
-
 # PartitionAlloc have limited support for MSVC's cl.exe compiler. It can only
 # access the generate "buildflags" and the "raw_ptr" definitions implemented
 # with RawPtrNoOpImpl. Everything else is considered not supported.
@ -82,9 +32,8 @@ if (is_nacl) {
 # foreground mode compared to background mode
 # (see `PartitionRoot::AdjustFor(Background|Foreground)`).
 #
-# Foreground/background modes are used by default on macOS and Windows so this
-# must be true on these platforms. It's also true on other platforms to allow
-# experiments.
+# Foreground/background modes are used by default on macOS so this must be
+# true on that platform. It's also true on other platforms to allow experiments.
 #
 # TODO(crbug.com/329199197): Clean this up when experiments are complete.
 use_large_empty_slot_span_ring = true
@ -98,12 +47,6 @@ has_memory_tagging =
    current_cpu == "arm64" && is_clang && !is_asan && is_linux && current_os != "openwrt"

 declare_args() {
-  # Debug configuration.
-  partition_alloc_is_debug = partition_alloc_is_debug_default
-
-  # Enable PA_DCHECKs in PartitionAlloc in release mode.
-  partition_alloc_dcheck_always_on = partition_alloc_dcheck_always_on_default
-
  # Causes all the allocations to be routed via allocator_shim.cc. Usually,
  # the allocator shim will, in turn, route them to PartitionAlloc, but
  # other allocators are also supported by the allocator shim.
@ -191,8 +134,8 @@ if (use_allocator_shim && is_win) {
  # If libcxx_is_shared=false, libc++ is a static library. All libc++ code
  # will be run inside the client. The above issue will disappear.
  assert(
-      !is_component_build || (!libcxx_is_shared && !partition_alloc_is_debug),
-      "The allocator shim for the Windows component build needs !libcxx_is_shared && !partition_alloc_is_debug.")
+      !is_component_build || (!libcxx_is_shared && !is_debug),
+      "The allocator shim for the Windows component build needs !libcxx_is_shared && !is_debug.")
 }

 declare_args() {
@ -228,8 +171,7 @@ declare_args() {
  # later verify the pattern remain unchanged to ensure there is no OOB write.
  # It comes with performance and memory cost, hence enabled only in debug.
  use_partition_cookie =
-      partition_alloc_is_debug || partition_alloc_dcheck_always_on ||
-      enable_ios_corruption_hardening
+      is_debug || dcheck_always_on || enable_ios_corruption_hardening

  # This will change partition cookie size to 4B or 8B, whichever equivalent to
  # size of InSlotMetadata. This option is useful for InSlotMetadata corruption
--- a/src/base/allocator/partition_allocator/src/partition_alloc/BUILD.gn
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/BUILD.gn
@ -35,8 +35,7 @@ enable_pointer_compression =

 # Duplicates the setup Chromium uses to define `DCHECK_IS_ON()`, but avails it
 # as a buildflag.
-partition_alloc_dchecks_are_on =
-    partition_alloc_is_debug || partition_alloc_dcheck_always_on
+dchecks_are_on = is_debug || dcheck_always_on

 # Building PartitionAlloc for Windows component build.
 # Currently use build_with_chromium not to affect any third_party code,
@ -123,34 +122,12 @@ source_set("buildflag_macro") {
  public_configs = [ ":public_includes" ]
 }

-# When developers are repeatedly growing a buffer with `realloc`, they are
-# expected to request a new size that is larger than the current size by
-# some growth factor. This growth factor allows to amortize the cost of
-# memcpy. Unfortunately, some nVidia drivers have a bug where they repeatedly
-# increase the buffer by 4144 byte only.
-#
-# In particular, most Skia Linux bots are using the affected nVidia driver. So
-# this flag is used as a workaround for Skia standalone, not in production.
-#
-# External link:
-#   https://forums.developer.nvidia.com/t/550-54-14-very-bad-performance-due-to-bunch-of-reallocations-during-glcore-initialization/287027
-#
-# Internal discussion at @chrome-memory-safety:
-#   https://groups.google.com/a/google.com/d/msgid/chrome-memory-safety/CAAzos5HrexY2njz2YzWrffTq1xEfkx15GVpSvHUyQED6wBSXvA%40mail.gmail.com?utm_medium=email&utm_source=footer
-declare_args() {
-  partition_alloc_realloc_growth_factor_mitigation = false
-}
-
 pa_buildflag_header("buildflags") {
  header = "buildflags.h"
  flags = [
    "ASSERT_CPP_20=$assert_cpp20",
    "BACKUP_REF_PTR_EXTRA_OOB_CHECKS=$backup_ref_ptr_extra_oob_checks",
    "BACKUP_REF_PTR_POISON_OOB_PTR=$backup_ref_ptr_poison_oob_ptr",
-    "CAN_UNWIND_WITH_FRAME_POINTERS=$can_unwind_with_frame_pointers",
-    "DCHECKS_ARE_ON=$partition_alloc_dchecks_are_on",
-    "DCHECK_IS_CONFIGURABLE=$dcheck_is_configurable",
-    "ENABLE_ALLOCATOR_SHIM_PARTITION_ALLOC_DISPATCH_WITH_ADVANCED_CHECKS_SUPPORT=$enable_allocator_shim_partition_alloc_dispatch_with_advanced_checks_support",
    "ENABLE_BACKUP_REF_PTR_FEATURE_FLAG=$enable_backup_ref_ptr_feature_flag",
    "ENABLE_BACKUP_REF_PTR_INSTANCE_TRACER=$enable_backup_ref_ptr_instance_tracer",
    "ENABLE_BACKUP_REF_PTR_SLOW_CHECKS=$enable_backup_ref_ptr_slow_checks",
@ -165,7 +142,6 @@ pa_buildflag_header("buildflags") {
    "ENABLE_POINTER_SUBTRACTION_CHECK=$enable_pointer_subtraction_check",
    "ENABLE_SHADOW_METADATA_FOR_64_BITS_POINTERS=$enable_shadow_metadata",
    "ENABLE_THREAD_ISOLATION=$enable_pkeys",
-    "EXPENSIVE_DCHECKS_ARE_ON=$enable_expensive_dchecks",
    "FORCE_DISABLE_BACKUP_REF_PTR_FEATURE=$force_disable_backup_ref_ptr_feature",
    "FORCE_ENABLE_RAW_PTR_EXCLUSION=$force_enable_raw_ptr_exclusion",
    "FORWARD_THROUGH_MALLOC=$forward_through_malloc",
@ -175,11 +151,10 @@ pa_buildflag_header("buildflags") {
    "IS_CASTOS=$is_castos",
    "IS_CAST_ANDROID=$is_cast_android",
    "IS_CHROMEOS=$is_chromeos",
-    "IS_DEBUG=$partition_alloc_is_debug",
+    "IS_DEBUG=$is_debug",
    "RAW_PTR_ZERO_ON_CONSTRUCT=$raw_ptr_zero_on_construct",
    "RAW_PTR_ZERO_ON_DESTRUCT=$raw_ptr_zero_on_destruct",
    "RAW_PTR_ZERO_ON_MOVE=$raw_ptr_zero_on_move",
-    "REALLOC_GROWTH_FACTOR_MITIGATION=$partition_alloc_realloc_growth_factor_mitigation",
    "RECORD_ALLOC_INFO=$record_alloc_info",
    "SMALLER_PARTITION_COOKIE=$smaller_partition_cookie",
    "STACK_SCAN_SUPPORTED=$stack_scan_supported",
@ -195,6 +170,11 @@ pa_buildflag_header("buildflags") {
    "USE_RAW_PTR_ASAN_UNOWNED_IMPL=$use_raw_ptr_asan_unowned_impl",
    "USE_RAW_PTR_BACKUP_REF_IMPL=$use_raw_ptr_backup_ref_impl",
    "USE_RAW_PTR_HOOKABLE_IMPL=$use_raw_ptr_hookable_impl",
+    "ENABLE_ALLOCATOR_SHIM_PARTITION_ALLOC_DISPATCH_WITH_ADVANCED_CHECKS_SUPPORT=$enable_allocator_shim_partition_alloc_dispatch_with_advanced_checks_support",
+    "DCHECKS_ARE_ON=$dchecks_are_on",
+    "EXPENSIVE_DCHECKS_ARE_ON=$enable_expensive_dchecks",
+    "DCHECK_IS_CONFIGURABLE=$dcheck_is_configurable",
+    "CAN_UNWIND_WITH_FRAME_POINTERS=$can_unwind_with_frame_pointers",
  ]
 }

@ -350,7 +330,7 @@ if (is_clang_or_gcc) {
    }
  }

-  if (enable_pkeys && partition_alloc_is_debug) {
+  if (enable_pkeys && is_debug) {
    config("no_stack_protector") {
      cflags = [ "-fno-stack-protector" ]
    }
@ -462,7 +442,6 @@ if (is_clang_or_gcc) {
      "partition_page_constants.h",
      "partition_root.cc",
      "partition_root.h",
-      "partition_shared_mutex.h",
      "partition_stats.cc",
      "partition_stats.h",
      "partition_superpage_extent_entry.h",
@ -587,7 +566,7 @@ if (is_clang_or_gcc) {

    # We want to be able to test pkey mode without access to the default pkey.
    # This is incompatible with stack protectors since the TLS won't be pkey-tagged.
-    if (enable_pkeys && partition_alloc_is_debug) {
+    if (enable_pkeys && is_debug) {
      configs += [ ":no_stack_protector" ]
    }
  }
@ -620,7 +599,6 @@ if (is_clang_or_gcc) {
      "partition_alloc_base/debug/stack_trace.cc",
      "partition_alloc_base/debug/stack_trace.h",
      "partition_alloc_base/export_template.h",
-      "partition_alloc_base/files/platform_file.h",
      "partition_alloc_base/immediate_crash.h",
      "partition_alloc_base/log_message.cc",
      "partition_alloc_base/log_message.h",
@ -666,7 +644,6 @@ if (is_clang_or_gcc) {
      "partition_alloc_base/time/time.h",
      "partition_alloc_base/time/time_override.cc",
      "partition_alloc_base/time/time_override.h",
-      "partition_alloc_base/types/same_as_any.h",
      "partition_alloc_base/types/strong_alias.h",
      "partition_alloc_base/win/win_handle_types.h",
      "partition_alloc_base/win/win_handle_types_list.inc",
@ -810,6 +787,8 @@ if (is_clang_or_gcc) {
  }

  component("allocator_shim") {
+    visibility = [ ":*" ]
+
    sources = []
    deps = []
    all_dependent_configs = []
@ -1035,7 +1014,7 @@ if (build_with_chromium) {
      ]
    }

-    if (enable_pkeys && partition_alloc_is_debug && !is_component_build) {
+    if (enable_pkeys && is_debug && !is_component_build) {
      # This test requires RELRO, which is not enabled in component builds.
      # Also, require a debug build, since we only disable stack protectors in
      # debug builds in PartitionAlloc (see below why it's needed).
--- a/src/base/allocator/partition_allocator/src/partition_alloc/address_space_randomization.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/address_space_randomization.h
@ -292,7 +292,7 @@ AslrMask(uintptr_t bits) {

 #endif  // PA_BUILDFLAG(PA_ARCH_CPU_32_BITS)

-// clang-format on
+    // clang-format on

 }  // namespace internal

--- a/src/base/allocator/partition_allocator/src/partition_alloc/allocation_guard.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/allocation_guard.cc
@ -3,7 +3,6 @@
 // found in the LICENSE file.

 #include "partition_alloc/allocation_guard.h"
-
 #include "partition_alloc/partition_alloc_base/immediate_crash.h"
 #include "partition_alloc/partition_alloc_config.h"

--- a/src/base/allocator/partition_allocator/src/partition_alloc/extended_api.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/extended_api.cc
@ -77,17 +77,7 @@ ThreadCacheProcessScopeForTesting::ThreadCacheProcessScopeForTesting(
    // Replace ThreadCache's PartitionRoot.
    ThreadCache::SwapForTesting(root_);
  } else {
-    bool regular_was_disabled = !regular_was_enabled_;
-#if PA_BUILDFLAG(IS_WIN)
-    // ThreadCache may be tombstone because of the previous test. In the
-    // case, we have to remove tombstone and re-create ThreadCache for
-    // a new test.
-    if (ThreadCache::IsTombstone(ThreadCache::Get())) {
-      ThreadCache::RemoveTombstoneForTesting();
-      regular_was_disabled = true;
-    }
-#endif
-    if (regular_was_disabled) {
+    if (!regular_was_enabled_) {
      EnablePartitionAllocThreadCacheForRootIfDisabled(root_);
      ThreadCache::SwapForTesting(root_);
    }
@ -99,7 +89,6 @@ ThreadCacheProcessScopeForTesting::ThreadCacheProcessScopeForTesting(
 #endif  // PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)

  PA_CHECK(ThreadCache::Get());
-  PA_CHECK(!ThreadCache::IsTombstone(ThreadCache::Get()));
 }

 ThreadCacheProcessScopeForTesting::~ThreadCacheProcessScopeForTesting() {
--- a/src/base/allocator/partition_allocator/src/partition_alloc/internal_allocator.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/internal_allocator.cc
@ -37,4 +37,8 @@ void InternalPartitionAllocated::operator delete(void* ptr, std::align_val_t) {
  InternalAllocatorRoot().Free<FreeFlags::kNoHooks>(ptr);
 }

+// A deleter for `std::unique_ptr<T>`.
+void InternalPartitionDeleter::operator()(void* ptr) const {
+  InternalAllocatorRoot().Free<FreeFlags::kNoHooks>(ptr);
+}
 }  // namespace partition_alloc::internal
--- a/src/base/allocator/partition_allocator/src/partition_alloc/internal_allocator.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/internal_allocator.h
@ -48,6 +48,8 @@ T* ConstructAtInternalPartition(Args&&... args) {
 }

 // Destroy an object on heap in the internal partition.
+// TODO(crbug.com/40274826) This is an unused function. Start using it in tests
+// and/or in production code.
 template <typename T>
 void DestroyAtInternalPartition(T* ptr) {
  // Destroying an array is not supported.
--- a/src/base/allocator/partition_allocator/src/partition_alloc/internal_allocator_forward.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/internal_allocator_forward.h
@ -67,13 +67,14 @@ template <typename T, typename... Args>
 T* ConstructAtInternalPartition(Args&&... args);

 // Destroy an object on heap in the internal partition.
+// TODO(crbug.com/40274826) This is an unused function. Start using it in tests
+// and/or in production code.
 template <typename T>
 void DestroyAtInternalPartition(T* ptr);

 // A deleter for `std::unique_ptr<T>`.
-template <typename T>
-struct InternalPartitionDeleter final {
-  void operator()(T* ptr) const { DestroyAtInternalPartition(ptr); }
+struct PA_COMPONENT_EXPORT(PARTITION_ALLOC) InternalPartitionDeleter final {
+  void operator()(void* ptr) const;
 };

 }  // namespace partition_alloc::internal
--- a/src/base/allocator/partition_allocator/src/partition_alloc/lightweight_quarantine.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/lightweight_quarantine.cc
@ -19,10 +19,7 @@ class PA_SCOPED_LOCKABLE
 public:
  PA_ALWAYS_INLINE explicit CompileTimeConditionalScopedGuard(Lock& lock)
      PA_EXCLUSIVE_LOCK_FUNCTION(lock) {}
-  // For some reason, defaulting this causes a thread safety annotation failure.
-  PA_ALWAYS_INLINE
-  ~CompileTimeConditionalScopedGuard()  // NOLINT(modernize-use-equals-default)
-      PA_UNLOCK_FUNCTION() {}
+  PA_ALWAYS_INLINE ~CompileTimeConditionalScopedGuard() PA_UNLOCK_FUNCTION() {}
 };

 template <>
@ -74,12 +71,7 @@ LightweightQuarantineBranch::LightweightQuarantineBranch(
    const LightweightQuarantineBranchConfig& config)
    : root_(root),
      lock_required_(config.lock_required),
-      branch_capacity_in_bytes_(config.branch_capacity_in_bytes) {
-  if (lock_required_) {
-    to_be_freed_working_memory_ =
-        ConstructAtInternalPartition<ToBeFreedArray>();
-  }
-}
+      branch_capacity_in_bytes_(config.branch_capacity_in_bytes) {}

 LightweightQuarantineBranch::LightweightQuarantineBranch(
    LightweightQuarantineBranch&& b)
@ -90,19 +82,10 @@ LightweightQuarantineBranch::LightweightQuarantineBranch(
      branch_capacity_in_bytes_(
          b.branch_capacity_in_bytes_.load(std::memory_order_relaxed)) {
  b.branch_size_in_bytes_ = 0;
-  if (lock_required_) {
-    to_be_freed_working_memory_.store(b.to_be_freed_working_memory_.exchange(
-                                          nullptr, std::memory_order_relaxed),
-                                      std::memory_order_relaxed);
-  }
 }

 LightweightQuarantineBranch::~LightweightQuarantineBranch() {
  Purge();
-  if (lock_required_) {
-    DestroyAtInternalPartition(to_be_freed_working_memory_.exchange(
-        nullptr, std::memory_order_relaxed));
-  }
 }

 bool LightweightQuarantineBranch::IsQuarantinedForTesting(void* object) {
@ -168,26 +151,16 @@ bool LightweightQuarantineBranch::QuarantineInternal(
    const size_t random_index = random_.RandUint32() % slots_.size();
    std::swap(slots_[random_index], slots_.back());
  } else {
-    std::unique_ptr<ToBeFreedArray, InternalPartitionDeleter<ToBeFreedArray>>
-        to_be_freed;
+    ToBeFreedArray to_be_freed;
    size_t num_of_slots = 0;

    {
      CompileTimeConditionalScopedGuard<lock_required> guard(lock_);

-      // Borrow the reserved working memory from to_be_freed_working_memory_,
-      // and set nullptr to it indicating that it's in use.
-      to_be_freed.reset(to_be_freed_working_memory_.exchange(nullptr));
-      if (!to_be_freed) {
-        // When the reserved working memory has already been in use by another
-        // thread, fall back to allocate another chunk of working memory.
-        to_be_freed.reset(ConstructAtInternalPartition<ToBeFreedArray>());
-      }
-
      // Dequarantine some entries as required. Save the objects to be
      // deallocated into `to_be_freed`.
      PurgeInternalWithDefferedFree(capacity_in_bytes - usable_size,
-                                    *to_be_freed, num_of_slots);
+                                    to_be_freed, num_of_slots);

      // Put the entry onto the list.
      branch_size_in_bytes_ += usable_size;
@ -200,17 +173,7 @@ bool LightweightQuarantineBranch::QuarantineInternal(
    }

    // Actually deallocate the dequarantined objects.
-    BatchFree(*to_be_freed, num_of_slots);
-
-    // Return the possibly-borrowed working memory to
-    // to_be_freed_working_memory_. It doesn't matter much if it's really
-    // borrowed or locally-allocated. The important facts are 1) to_be_freed is
-    // non-null, and 2) to_be_freed_working_memory_ may likely be null (because
-    // this or another thread has already borrowed it). It's simply good to make
-    // to_be_freed_working_memory_ non-null whenever possible. Maybe yet another
-    // thread would be about to borrow the working memory.
-    to_be_freed.reset(
-        to_be_freed_working_memory_.exchange(to_be_freed.release()));
+    BatchFree(to_be_freed, num_of_slots);
  }

  // Update stats (not locked).
--- a/src/base/allocator/partition_allocator/src/partition_alloc/lightweight_quarantine.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/lightweight_quarantine.h
@ -217,17 +217,6 @@ class PA_COMPONENT_EXPORT(PARTITION_ALLOC) LightweightQuarantineBranch {
  // Using `std::atomic` here so that other threads can update this value.
  std::atomic_size_t branch_capacity_in_bytes_;

-  // This working memory is temporarily needed only while dequarantining
-  // objects in slots_ when lock_required_ is true. However, allocating this
-  // working memory on stack may cause stack overflow [1]. Plus, it's non-
-  // negligible perf penalty to allocate and deallocate this working memory on
-  // heap only while dequarantining. So, we reserve one chunk of working memory
-  // on heap during the entire lifetime of this branch object and try to reuse
-  // this working memory among threads. Only when thread contention occurs, we
-  // allocate and deallocate another chunk of working memory.
-  // [1] https://issues.chromium.org/issues/387508217
-  std::atomic<ToBeFreedArray*> to_be_freed_working_memory_ = nullptr;
-
  friend class LightweightQuarantineRoot;
 };

--- a/src/base/allocator/partition_allocator/src/partition_alloc/page_allocator_constants.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/page_allocator_constants.h
@ -26,7 +26,7 @@
 #define PAGE_ALLOCATOR_CONSTANTS_DECLARE_CONSTEXPR __attribute__((const))

 #elif (PA_BUILDFLAG(IS_ANDROID) && PA_BUILDFLAG(PA_ARCH_CPU_64_BITS)) || \
-    (PA_BUILDFLAG(IS_LINUX) && PA_BUILDFLAG(PA_ARCH_CPU_ARM64)) ||       \
+    (PA_BUILDFLAG(IS_LINUX) && PA_BUILDFLAG(PA_ARCH_CPU_ARM64)) || \
    (PA_BUILDFLAG(IS_LINUX) && PA_BUILDFLAG(PA_ARCH_CPU_PPC64))
 // This should work for all POSIX (if needed), but currently all other
 // supported OS/architecture combinations use either hard-coded values
@ -39,7 +39,6 @@
 #define PAGE_ALLOCATOR_CONSTANTS_DECLARE_CONSTEXPR __attribute__((const))

 #include <unistd.h>
-
 #include <atomic>

 namespace partition_alloc::internal {
@ -70,30 +69,9 @@ extern PageCharacteristics page_characteristics;

 // Ability to name anonymous VMAs is available on some, but not all Linux-based
 // systems.
-#if PA_BUILDFLAG(IS_ANDROID) || PA_BUILDFLAG(IS_LINUX) || \
-    PA_BUILDFLAG(IS_CHROMEOS)
+#if PA_BUILDFLAG(IS_ANDROID) || PA_BUILDFLAG(IS_LINUX)
 #include <sys/prctl.h>

-#if (PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)) && \
-    !(defined(PR_SET_VMA) && defined(PR_SET_VMA_ANON_NAME))
-
-// The PR_SET_VMA* symbols are originally from
-// https://android.googlesource.com/platform/bionic/+/lollipop-release/libc/private/bionic_prctl.h
-// and were subsequently added to mainline Linux in Jan 2022, see
-// https://github.com/torvalds/linux/commit/9a10064f5625d5572c3626c1516e0bebc6c9fe9b.
-//
-// Define them to support compiling with older headers.
-#if !defined(PR_SET_VMA)
-#define PR_SET_VMA 0x53564d41
-#endif
-
-#if !defined(PR_SET_VMA_ANON_NAME)
-#define PR_SET_VMA_ANON_NAME 0
-#endif
-
-#endif  // (PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)) &&
-        // !(defined(PR_SET_VMA) && defined(PR_SET_VMA_ANON_NAME))
-
 #if defined(PR_SET_VMA) && defined(PR_SET_VMA_ANON_NAME)
 #define LINUX_NAME_REGION 1
 #endif
--- a/src/base/allocator/partition_allocator/src/partition_alloc/page_allocator_internals_posix.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/page_allocator_internals_posix.cc
@ -150,7 +150,7 @@ void NameRegion(void* start, size_t length, PageTag page_tag) {
      PA_NOTREACHED();
  }

-  // No error checking on purpose, used for debugging only.
+  // No error checking on purpose, testing only.
  prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, start, length, name);
 }

@ -200,7 +200,14 @@ bool UseMapJit() {
 }
 #elif PA_BUILDFLAG(IS_IOS)
 bool UseMapJit() {
+// Always enable MAP_JIT in simulator as it is supported unconditionally.
+#if TARGET_IPHONE_SIMULATOR
  return true;
+#else
+  // TODO(crbug.com/40255826): Fill this out when the API it is
+  // available.
+  return false;
+#endif  // TARGET_IPHONE_SIMULATOR
 }
 #endif  // PA_BUILDFLAG(IS_IOS)

--- a/src/base/allocator/partition_allocator/src/partition_alloc/page_allocator_internals_posix.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/page_allocator_internals_posix.h
@ -83,13 +83,6 @@ uintptr_t SystemAllocPagesInternal(uintptr_t hint,
          PageAccessibilityConfiguration::kInaccessibleWillJitLater &&
      kUseMapJit) {
    map_flags |= MAP_JIT;
-    // iOS devices do not support toggling the page permissions after a MAP_JIT
-    // call, they must be set initially. iOS has per-thread W^X state that
-    // takes precedence over the mapping's permissions for MAP_JIT regions.
-    // See https://developer.apple.com/forums/thread/672804
-#if PA_BUILDFLAG(IS_IOS)
-    access_flag = PROT_READ | PROT_WRITE | PROT_EXEC;
-#endif
  }
 #endif

--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_address_space.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_address_space.cc
@ -19,7 +19,6 @@
 #include "partition_alloc/partition_alloc_base/bits.h"
 #include "partition_alloc/partition_alloc_base/compiler_specific.h"
 #include "partition_alloc/partition_alloc_base/debug/alias.h"
-#include "partition_alloc/partition_alloc_base/files/platform_file.h"
 #include "partition_alloc/partition_alloc_check.h"
 #include "partition_alloc/partition_alloc_config.h"
 #include "partition_alloc/partition_alloc_constants.h"
@ -90,12 +89,9 @@ std::ptrdiff_t PartitionAddressSpace::brp_pool_shadow_offset_ = 0;
 std::ptrdiff_t PartitionAddressSpace::configurable_pool_shadow_offset_ = 0;

 // File descriptors for shared mappings.
-base::PlatformFile PartitionAddressSpace::regular_pool_fd_ =
-    base::kInvalidPlatformFile;
-base::PlatformFile PartitionAddressSpace::brp_pool_fd_ =
-    base::kInvalidPlatformFile;
-base::PlatformFile PartitionAddressSpace::configurable_pool_fd_ =
-    base::kInvalidPlatformFile;
+int PartitionAddressSpace::regular_pool_fd_ = -1;
+int PartitionAddressSpace::brp_pool_fd_ = -1;
+int PartitionAddressSpace::configurable_pool_fd_ = -1;

 uintptr_t PartitionAddressSpace::pool_shadow_address_ =
    PartitionAddressSpace::kUninitializedPoolBaseAddress;
@ -156,6 +152,9 @@ void PartitionAddressSpace::Init() {

  const size_t core_pool_size = CorePoolSize();

+  // TODO(crbug.com/40238514): Support PA_ENABLE_SHADOW_METADATA.
+  int pools_fd = -1;
+
  size_t glued_pool_sizes = core_pool_size * 2;
  // Note, BRP pool requires to be preceded by a "forbidden zone", which is
  // conveniently taken care of by the last guard page of the regular pool.
@ -163,7 +162,7 @@ void PartitionAddressSpace::Init() {
      AllocPages(glued_pool_sizes, glued_pool_sizes,
                 PageAccessibilityConfiguration(
                     PageAccessibilityConfiguration::kInaccessible),
-                 PageTag::kPartitionAlloc);
+                 PageTag::kPartitionAlloc, pools_fd);
 #if PA_BUILDFLAG(IS_ANDROID)
  // On Android, Adreno-GSL library fails to mmap if we snatch address
  // 0x400000000. Find a different address instead.
@ -172,7 +171,7 @@ void PartitionAddressSpace::Init() {
        AllocPages(glued_pool_sizes, glued_pool_sizes,
                   PageAccessibilityConfiguration(
                       PageAccessibilityConfiguration::kInaccessible),
-                   PageTag::kPartitionAlloc);
+                   PageTag::kPartitionAlloc, pools_fd);
    FreePages(setup_.regular_pool_base_address_, glued_pool_sizes);
    setup_.regular_pool_base_address_ = new_base_address;
  }
@ -357,10 +356,9 @@ void PartitionAddressSpace::UninitThreadIsolatedPoolForTesting() {

 namespace {

-base::PlatformFile CreateAnonymousFileForMapping(
-    [[maybe_unused]] const char* name,
-    [[maybe_unused]] size_t size) {
-  base::PlatformFile fd = base::kInvalidPlatformFile;
+int CreateAnonymousFileForMapping([[maybe_unused]] const char* name,
+                                  [[maybe_unused]] size_t size) {
+  int fd = -1;
 #if PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)
  // TODO(crbug.com/40238514): if memfd_secret() is available, try
  // memfd_secret() first.
@ -398,7 +396,7 @@ void PartitionAddressSpace::InitShadowMetadata(PoolHandleMask mask) {

  // Set up a memory file for the given pool, and init |offset|.
  if (ContainsFlags(mask, PoolHandleMask::kConfigurable)) {
-    if (configurable_pool_fd_ == base::kInvalidPlatformFile) {
+    if (configurable_pool_fd_ == -1) {
      PA_DCHECK(pool_shadow_address_);
      PA_DCHECK(configurable_pool_shadow_offset_ == 0);
      configurable_pool_fd_ = CreateAnonymousFileForMapping(
@ -409,7 +407,7 @@ void PartitionAddressSpace::InitShadowMetadata(PoolHandleMask mask) {
    }
  }
  if (ContainsFlags(mask, PoolHandleMask::kBRP)) {
-    if (brp_pool_fd_ == base::kInvalidPlatformFile) {
+    if (brp_pool_fd_ == -1) {
      PA_DCHECK(pool_shadow_address_);
      PA_DCHECK(brp_pool_shadow_offset_ == 0);
      brp_pool_fd_ = CreateAnonymousFileForMapping("brp_pool_shadow",
@ -420,7 +418,7 @@ void PartitionAddressSpace::InitShadowMetadata(PoolHandleMask mask) {
    }
  }
  if (ContainsFlags(mask, PoolHandleMask::kRegular)) {
-    if (regular_pool_fd_ == base::kInvalidPlatformFile) {
+    if (regular_pool_fd_ == -1) {
      PA_DCHECK(pool_shadow_address_);
      PA_DCHECK(regular_pool_shadow_offset_ == 0);
      regular_pool_fd_ = CreateAnonymousFileForMapping("regular_pool_shadow",
@ -439,7 +437,7 @@ void PartitionAddressSpace::MapMetadata(uintptr_t super_page,
  PA_DCHECK(pool_shadow_address_);
  PA_DCHECK(0u == (super_page & kSuperPageOffsetMask));
  std::ptrdiff_t offset;
-  base::PlatformFile pool_fd = base::kInvalidPlatformFile;
+  int pool_fd = -1;
  uintptr_t base_address;

  if (IsInRegularPool(super_page)) {
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_address_space.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_address_space.h
@ -15,7 +15,6 @@
 #include "partition_alloc/partition_alloc_base/bits.h"
 #include "partition_alloc/partition_alloc_base/compiler_specific.h"
 #include "partition_alloc/partition_alloc_base/component_export.h"
-#include "partition_alloc/partition_alloc_base/files/platform_file.h"
 #include "partition_alloc/partition_alloc_base/notreached.h"
 #include "partition_alloc/partition_alloc_check.h"
 #include "partition_alloc/partition_alloc_config.h"
@ -222,15 +221,15 @@ class PA_COMPONENT_EXPORT(PARTITION_ALLOC) PartitionAddressSpace {

 #if PA_CONFIG(ENABLE_SHADOW_METADATA)
  PA_ALWAYS_INLINE static bool IsShadowMetadataEnabledOnRegularPool() {
-    return regular_pool_fd_ != base::kInvalidPlatformFile;
+    return regular_pool_fd_ != -1;
  }

  PA_ALWAYS_INLINE static bool IsShadowMetadataEnabledOnBRPPool() {
-    return brp_pool_fd_ != base::kInvalidPlatformFile;
+    return brp_pool_fd_ != -1;
  }

  PA_ALWAYS_INLINE static bool IsShadowMetadataEnabledOnConfigurablePool() {
-    return configurable_pool_fd_ != base::kInvalidPlatformFile;
+    return configurable_pool_fd_ != -1;
  }

  PA_ALWAYS_INLINE static bool IsShadowMetadataEnabled(pool_handle pool) {
@ -455,9 +454,10 @@ class PA_COMPONENT_EXPORT(PARTITION_ALLOC) PartitionAddressSpace {
  static std::ptrdiff_t regular_pool_shadow_offset_;
  static std::ptrdiff_t brp_pool_shadow_offset_;
  static std::ptrdiff_t configurable_pool_shadow_offset_;
-  static base::PlatformFile regular_pool_fd_;
-  static base::PlatformFile brp_pool_fd_;
-  static base::PlatformFile configurable_pool_fd_;
+  // TODO(crbug.com/40238514): Use platform file handles instead of |int|.
+  static int regular_pool_fd_;
+  static int brp_pool_fd_;
+  static int configurable_pool_fd_;
  static uintptr_t pool_shadow_address_;
 #endif  // PA_CONFIG(ENABLE_SHADOW_METADATA)

--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc-inl.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc-inl.h
@ -65,7 +65,7 @@ PA_ALWAYS_INLINE void DebugMemset(void* ptr, int value, size_t size) {
  // faster. Note that for direct-mapped allocations, memory is decomitted at
  // free() time, so freed memory usage cannot happen.

-#if PA_BUILDFLAG(ENABLE_THREAD_ISOLATION) && PA_BUILDFLAG(ENABLE_PKEYS)
+#if PA_BUILDFLAG(ENABLE_THREAD_ISOLATION)
  LiftThreadIsolationScope lift_thread_isolation_restrictions;
 #endif
  size_t size_to_memset = std::min(size, size_t{1} << 19);
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/check.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/check.h
@ -20,12 +20,11 @@
 // This header defines the CHECK, DCHECK, and DPCHECK macros.
 //
 // CHECK dies with a fatal error if its condition is not true. It is not
-// controlled by PA_BUILDFLAG(IS_DEBUG), so the check will be executed
-// regardless of compilation mode.
+// controlled by NDEBUG, so the check will be executed regardless of compilation
+// mode.
 //
-// DCHECK, the "debug mode" check, is enabled depending on
-// PA_BUILDFLAG(IS_DEBUG) and PA_BUILDFLAG(DCHECK_ALWAYS_ON), and its severity
-// depends on PA_BUILDFLAG(DCHECK_IS_CONFIGURABLE).
+// DCHECK, the "debug mode" check, is enabled depending on NDEBUG and
+// DCHECK_ALWAYS_ON, and its severity depends on DCHECK_IS_CONFIGURABLE.
 //
 // (D)PCHECK is like (D)CHECK, but includes the system error code (c.f.
 // perror(3)).
@ -142,9 +141,9 @@ class PA_COMPONENT_EXPORT(PARTITION_ALLOC_BASE) NotImplemented

 }  // namespace check_error

-#if defined(OFFICIAL_BUILD) && PA_BUILDFLAG(IS_DEBUG)
+#if defined(OFFICIAL_BUILD) && !defined(NDEBUG)
 #error "Debug builds are not expected to be optimized as official builds."
-#endif  // defined(OFFICIAL_BUILD) && BUILDFLAG(IS_DEBUG)
+#endif  // defined(OFFICIAL_BUILD) && !defined(NDEBUG)

 #if defined(OFFICIAL_BUILD) && !PA_BUILDFLAG(DCHECKS_ARE_ON)

--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/compiler_specific.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/compiler_specific.h
@ -6,7 +6,6 @@
 #define PARTITION_ALLOC_PARTITION_ALLOC_BASE_COMPILER_SPECIFIC_H_

 #include "partition_alloc/build_config.h"
-#include "partition_alloc/buildflags.h"

 // A wrapper around `__has_cpp_attribute()`, which is in C++20 and thus not yet
 // available for all targets PA supports (since PA's minimum C++ version is 17).
@ -88,7 +87,7 @@
 //
 // Since `ALWAYS_INLINE` is performance-oriented but can hamper debugging,
 // ignore it in debug mode.
-#if !PA_BUILDFLAG(IS_DEBUG)
+#if defined(NDEBUG)
 #if PA_HAS_CPP_ATTRIBUTE(clang::always_inline)
 #define PA_ALWAYS_INLINE [[clang::always_inline]] inline
 #elif PA_HAS_CPP_ATTRIBUTE(gnu::always_inline)
@ -96,7 +95,7 @@
 #elif defined(PA_COMPILER_MSVC)
 #define PA_ALWAYS_INLINE __forceinline
 #endif
-#endif  // !PA_BUILDFLAG(IS_DEBUG)
+#endif
 #if !defined(PA_ALWAYS_INLINE)
 #define PA_ALWAYS_INLINE inline
 #endif
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/cpu.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/cpu.cc
@ -97,7 +97,7 @@ uint64_t xgetbv(uint32_t xcr) {

 void CPU::Initialize() {
 #if PA_BUILDFLAG(PA_ARCH_CPU_X86_FAMILY)
-  int cpu_info[4] = {-1, 0, 0, 0};
+  int cpu_info[4] = {-1};

  // __cpuid with an InfoType argument of 0 returns the number of
  // valid Ids in CPUInfo[0] and the CPU identification string in
@ -112,7 +112,7 @@ void CPU::Initialize() {

  // Interpret CPU feature information.
  if (num_ids > 0) {
-    int cpu_info7[4] = {};
+    int cpu_info7[4] = {0};
    __cpuid(cpu_info, 1);
    if (num_ids >= 7) {
      __cpuid(cpu_info7, 7);
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/debug/alias.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/debug/alias.h
@ -35,7 +35,7 @@ namespace partition_alloc::internal::base::debug {
 //   strncpy(name_copy, p->name, sizeof(name_copy)-1);
 //   name_copy[sizeof(name_copy)-1] = '\0';;
 //   base::debug::alias(name_copy);
-//   NOTREACHED();
+//   CHECK(false);
 //
 // Case #2: Prevent a tail call into a function. This is useful to make sure the
 // function containing the call to base::debug::Alias() will be present in the
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/files/platform_file.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/files/platform_file.h
@ -1,39 +0,0 @@
-// Copyright 2017 The Chromium Authors
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef PARTITION_ALLOC_PARTITION_ALLOC_BASE_FILES_PLATFORM_FILE_H_
-#define PARTITION_ALLOC_PARTITION_ALLOC_BASE_FILES_PLATFORM_FILE_H_
-
-#include "partition_alloc/build_config.h"
-
-#if PA_BUILDFLAG(IS_WIN)
-#include "partition_alloc/partition_alloc_base/win/windows_types.h"
-#endif
-
-// This file defines platform-independent types for dealing with
-// platform-dependent files. If possible, use the higher-level base::File class
-// rather than these primitives.
-
-namespace partition_alloc::internal::base {
-
-#if PA_BUILDFLAG(IS_WIN)
-
-using PlatformFile = HANDLE;
-
-// It would be nice to make this constexpr but INVALID_HANDLE_VALUE is a
-// ((void*)(-1)) which Clang rejects since reinterpret_cast is technically
-// disallowed in constexpr. Visual Studio accepts this, however.
-const PlatformFile kInvalidPlatformFile = INVALID_HANDLE_VALUE;
-
-#elif PA_BUILDFLAG(IS_POSIX) || PA_BUILDFLAG(IS_FUCHSIA)
-
-using PlatformFile = int;
-
-inline constexpr PlatformFile kInvalidPlatformFile = -1;
-
-#endif
-
-}  // namespace partition_alloc::internal::base
-
-#endif  // PARTITION_ALLOC_PARTITION_ALLOC_BASE_FILES_PLATFORM_FILE_H_
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/numerics/safe_conversions_impl.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/numerics/safe_conversions_impl.h
@ -9,8 +9,6 @@
 #include <limits>
 #include <type_traits>

-#include "partition_alloc/buildflags.h"
-
 namespace partition_alloc::internal::base::internal {

 // The std library doesn't provide a binary max_exponent for integers, however
@ -85,13 +83,13 @@ constexpr typename std::make_unsigned<T>::type SafeUnsignedAbs(T value) {
 // TODO(jschuh): Debug builds don't reliably propagate constants, so we restrict
 // some accelerated runtime paths to release builds until this can be forced
 // with consteval support in C++20 or C++23.
-#if PA_BUILDFLAG(IS_DEBUG)
-inline constexpr bool kEnableAsmCode = false;
+#if defined(NDEBUG)
+constexpr bool kEnableAsmCode = true;
 #else
-inline constexpr bool kEnableAsmCode = true;
+constexpr bool kEnableAsmCode = false;
 #endif

-// Forces a crash, like a NOTREACHED(). Used for numeric boundary errors.
+// Forces a crash, like a CHECK(false). Used for numeric boundary errors.
 // Also used in a constexpr template to trigger a compilation failure on
 // an error condition.
 struct CheckOnFailure {
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/posix/eintr_wrapper.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/posix/eintr_wrapper.h
@ -18,7 +18,6 @@
 #define PARTITION_ALLOC_PARTITION_ALLOC_BASE_POSIX_EINTR_WRAPPER_H_

 #include "partition_alloc/build_config.h"
-#include "partition_alloc/buildflags.h"

 #if PA_BUILDFLAG(IS_POSIX)
 #include <cerrno>
@ -32,7 +31,7 @@ template <typename Fn>
 inline auto WrapEINTR(Fn fn) {
  return [fn](auto&&... args) {
    int out = -1;
-#if !PA_BUILDFLAG(IS_DEBUG)
+#if defined(NDEBUG)
    while (true)
 #else
    for (int retry_count = 0; retry_count < 100; ++retry_count)
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/strings/cstring_builder.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/strings/cstring_builder.h
@ -7,8 +7,13 @@

 #include <cstddef>

+#include "partition_alloc/build_config.h"
 #include "partition_alloc/partition_alloc_base/component_export.h"

+#if !PA_BUILDFLAG(IS_WIN)
+#include <unistd.h>
+#endif
+
 namespace partition_alloc::internal::base::strings {

 // Similar to std::ostringstream, but creates a C string, i.e. nul-terminated
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/strings/safe_sprintf.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/strings/safe_sprintf.cc
@ -10,9 +10,8 @@
 #include <limits>

 #include "partition_alloc/build_config.h"
-#include "partition_alloc/buildflags.h"

-#if PA_BUILDFLAG(IS_DEBUG)
+#if !defined(NDEBUG)
 // In debug builds, we use RAW_CHECK() to print useful error messages, if
 // SafeSPrintf() is called with broken arguments.
 // As our contract promises that SafeSPrintf() can be called from any
@ -42,7 +41,7 @@
    if (x) {           \
    }                  \
  } while (0)
-#endif  // PA_BUILDFLAG(IS_DEBUG)
+#endif

 namespace partition_alloc::internal::base::strings {

@ -75,7 +74,7 @@ const char kUpCaseHexDigits[] = "0123456789ABCDEF";
 const char kDownCaseHexDigits[] = "0123456789abcdef";
 }  // namespace

-#if !PA_BUILDFLAG(IS_DEBUG)
+#if defined(NDEBUG)
 // We would like to define kSSizeMax as std::numeric_limits<ssize_t>::max(),
 // but C++ doesn't allow us to do that for constants. Instead, we have to
 // use careful casting and shifting. We later use a static_assert to
@ -83,7 +82,7 @@ const char kDownCaseHexDigits[] = "0123456789abcdef";
 namespace {
 const size_t kSSizeMax = kSSizeMaxConst;
 }
-#else   // !PA_BUILDFLAG(IS_DEBUG)
+#else   // defined(NDEBUG)
 // For efficiency, we really need kSSizeMax to be a constant. But for unit
 // tests, it should be adjustable. This allows us to verify edge cases without
 // having to fill the entire available address space. As a compromise, we make
@ -102,7 +101,7 @@ size_t GetSafeSPrintfSSizeMaxForTest() {
  return kSSizeMax;
 }
 }  // namespace internal
-#endif  // !PA_BUILDFLAG(IS_DEBUG)
+#endif  // defined(NDEBUG)

 namespace {
 class Buffer {
@ -112,7 +111,10 @@ class Buffer {
  // to ensure that the buffer is at least one byte in size, so that it fits
  // the trailing NUL that will be added by the destructor. The buffer also
  // must be smaller or equal to kSSizeMax in size.
-  Buffer(char* buffer, size_t size) : buffer_(buffer), size_(size - 1) {
+  Buffer(char* buffer, size_t size)
+      : buffer_(buffer),
+        size_(size - 1),  // Account for trailing NUL byte
+        count_(0) {
 // MSVS2013's standard library doesn't mark max() as constexpr yet. cl.exe
 // supports static_cast but doesn't really implement constexpr yet so it doesn't
 // complain, but clang does.
@ -274,7 +276,7 @@ class Buffer {
  // Number of bytes that would have been emitted to the buffer, if the buffer
  // was sufficiently big. This number always excludes the trailing NUL byte
  // and it is guaranteed to never grow bigger than kSSizeMax-1.
-  size_t count_ = 0;
+  size_t count_;
 };

 bool Buffer::IToASCII(bool sign,
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/threading/platform_thread_posix.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/threading/platform_thread_posix.cc
@ -20,7 +20,6 @@

 #if PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)
 #include <sys/syscall.h>
-
 #include <atomic>
 #endif

@ -28,10 +27,6 @@
 #include <zircon/process.h>
 #endif

-#if defined(__MUSL__)
-#include "partition_alloc/shim/allocator_shim.h"
-#endif
-
 namespace partition_alloc::internal::base {

 #if PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)
@ -63,22 +58,7 @@ thread_local bool g_is_main_thread = true;
 class InitAtFork {
 public:
  InitAtFork() {
-#if defined(__MUSL__)
-    allocator_shim::AllocatorDispatch d =
-        *allocator_shim::GetAllocatorDispatchChainHeadForTesting();
-    d.alloc_function = +[](size_t size, void*) -> void* {
-      // The size of the scratch fits struct atfork_funcs in Musl pthread_atfork.c.
-      static char scratch[5 * sizeof(void*)];
-      return size != sizeof(scratch) ? nullptr : scratch;
-    };
-    allocator_shim::InsertAllocatorDispatch(&d);
-#endif
-
    pthread_atfork(nullptr, nullptr, internal::InvalidateTidCache);
-
-#if defined(__MUSL__)
-    allocator_shim::RemoveAllocatorDispatchForTesting(&d);
-#endif
  }
 };

--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/types/same_as_any.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/types/same_as_any.h
@ -1,19 +0,0 @@
-// Copyright 2024 The Chromium Authors
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef PARTITION_ALLOC_PARTITION_ALLOC_BASE_TYPES_SAME_AS_ANY_H_
-#define PARTITION_ALLOC_PARTITION_ALLOC_BASE_TYPES_SAME_AS_ANY_H_
-
-#include <type_traits>
-
-namespace partition_alloc::internal::base {
-
-// True when `T` is any of the subsequent types.
-// TODO(crbug.com/344963951): Switch to a concept when C++20 is allowed.
-template <typename T, typename... Ts>
-inline constexpr bool kSameAsAny = (std::is_same_v<T, Ts> || ...);
-
-}  // namespace partition_alloc::internal::base
-
-#endif  // PARTITION_ALLOC_PARTITION_ALLOC_BASE_TYPES_SAME_AS_ANY_H_
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/win/windows_types.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_base/win/windows_types.h
@ -10,7 +10,6 @@

 // Needed for function prototypes.
 #include <specstrings.h>
-
 #include <cstdint>

 #ifdef __cplusplus
@ -42,11 +41,6 @@ typedef DWORD ULONG;
 typedef unsigned short WORD;
 typedef WORD UWORD;
 typedef WORD ATOM;
-#if defined(_WIN64)
-typedef int64_t PA_LONG_PTR, *PA_PLONG_PTR;
-#else
-typedef int32_t PA_LONG_PTR, *PA_PLONG_PTR;
-#endif

 // Forward declare some Windows struct/typedef sets.

@ -59,16 +53,6 @@ struct PA_CHROME_SRWLOCK {
  PVOID Ptr;
 };

-// Define some commonly used Windows constants. Note that the layout of these
-// macros - including internal spacing - must be 100% consistent with windows.h.
-
-// clang-format off
-
-#ifndef INVALID_HANDLE_VALUE
-// Work around there being two slightly different definitions in the SDK.
-#define INVALID_HANDLE_VALUE ((HANDLE)(PA_LONG_PTR)-1)
-#endif
-
 // The trailing white-spaces after this macro are required, for compatibility
 // with the definition in winnt.h.
 // clang-format off
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_check.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_check.h
@ -61,11 +61,11 @@

 // Expensive dchecks that run within *Scan. These checks are only enabled in
 // debug builds with dchecks enabled.
-#if PA_BUILDFLAG(IS_DEBUG)
+#if !defined(NDEBUG)
 #define PA_SCAN_DCHECK_IS_ON() PA_BUILDFLAG(DCHECKS_ARE_ON)
 #else
 #define PA_SCAN_DCHECK_IS_ON() 0
-#endif  // PA_BUILDFLAG(IS_DEBUG)
+#endif

 #if PA_SCAN_DCHECK_IS_ON()
 #define PA_SCAN_DCHECK(expr) PA_DCHECK(expr)
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_constants.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_alloc_constants.h
@ -63,7 +63,9 @@ enum class FreeFlags {
  kNoHooks = 1 << 1,  // Internal.
  // Quarantine for a while to ensure no UaF from on-stack pointers.
  kSchedulerLoopQuarantine = 1 << 2,
-  kMaxValue = kSchedulerLoopQuarantine,
+  // Zap the object region on `Free()`.
+  kZap = 1 << 3,
+  kMaxValue = kZap,
 };
 PA_DEFINE_OPERATORS_FOR_FLAGS(FreeFlags);
 }  // namespace internal
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_bucket.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_bucket.cc
@ -223,18 +223,6 @@ SlotSpanMetadata<MetadataKind::kReadOnly>* PartitionDirectMap(
  PartitionPageMetadata<MetadataKind::kReadOnly>* page_metadata = nullptr;

  {
-#if PA_CONFIG(ENABLE_SHADOW_METADATA)
-    // Because of the performance reason, PartitionRoot's lock is unlocked
-    // here. However this causes multi-thread issue when running
-    // EnableShadowMetadata(). If some thread is running PartitionDirectMap()
-    // and unlock PartitionRoot lock and also another thread is running
-    // EnableShadowMetadata(), the metadata page's permission will be modified
-    // by both threads and chrome will crash. c.f. crbug.com/378809882
-    // Be careful. This should not block PartitionDirectMap() in another thread.
-    internal::SharedLock shared_lock(
-        PartitionRoot::g_shadow_metadata_init_mutex_);
-#endif  // PA_CONFIG(ENABLE_SHADOW_METADATA)
-
    // Getting memory for direct-mapped allocations doesn't interact with the
    // rest of the allocator, but takes a long time, as it involves several
    // system calls. Although no mmap() (or equivalent) calls are made on
@ -684,7 +672,7 @@ PartitionBucket::AllocNewSlotSpan(PartitionRoot* root,
  for (auto* page = gap_start_page->ToWritable(root);
       page < gap_end_page->ToWritable(root); ++page) {
    PA_DCHECK(!page->is_valid);
-    page->has_valid_span_after_this = true;
+    page->has_valid_span_after_this = 1;
  }
  root->next_partition_page =
      adjusted_next_partition_page + slot_span_reservation_size;
@ -708,7 +696,7 @@ PartitionBucket::AllocNewSlotSpan(PartitionRoot* root,
    PA_DEBUG_DATA_ON_STACK("spancmt", slot_span_committed_size);

    root->RecommitSystemPagesForData(
-        slot_span_start, SlotSpanCommittedSize(root),
+        slot_span_start, slot_span_committed_size,
        PageAccessibilityDisposition::kRequireUpdate,
        slot_size <= kMaxMemoryTaggingSize);
  }
@ -1590,63 +1578,4 @@ void PartitionBucket::InitializeSlotSpanForGwpAsan(
  InitializeSlotSpan(slot_span, root);
 }

-size_t PartitionBucket::SlotSpanCommittedSize(PartitionRoot* root) const {
-  // With lazy commit, we certainly don't want to commit more than
-  // necessary. This is not reached, but keep the CHECK() as documentation.
-  PA_CHECK(!kUseLazyCommit);
-
-  // Memory is reserved in units of PartitionPage, but a given slot span may be
-  // smaller than the reserved area. For instance (assuming 4k pages), for a
-  // bucket where the slot span size is 40kiB, we reserve 4 PartitionPage = 16 *
-  // 4 = 48kiB, but only ever commit 40kiB out of it.
-  //
-  // This means that the address space then looks like, assuming that the
-  // PartitionPage next to it is committed:
-  //   [SlotSpan range, 40kiB]                       rw-p
-  //   [Unused area in the last PartitionPage, 8kiB] ---p
-  //   [Next PartitionPages, size unknown ]          rw-p
-  //
-  // So we have a "hole" of inaccessible memory, and 3 memory regions. If
-  // instead we commit the full PartitionPages, we get (due to the kernel
-  // merging neighboring regions with uniform permissions):
-  //
-  //   [SlotSpan range, 40kiB + Unused area, 8kiB + next PartitionPages] rw-p
-  //
-  // So 1 memory region rather then 3. This matters, because on Linux kernels,
-  // there is a maximum number of VMAs per process, with the default limit a bit
-  // less than 2^16, and Chromium sometimes hits the limit (see
-  // /proc/sys/vm/max_map_count for the current limit), largely because of
-  // PartitionAlloc contributing thousands of regions. Locally, on a Linux
-  // system, this reduces the number of PartitionAlloc regions by up to ~4x.
-  //
-  // Why is it safe?
-  // The extra memory is not used by anything, so committing it doesn't make a
-  // difference. It makes it accessible though.
-  //
-  // How much does it cost?
-  // Almost nothing. On Linux, "committing" memory merely changes its
-  // permissions, it doesn't cost any memory until the pages are touched, which
-  // they are not. However, mprotect()-ed areas that are writable count towards
-  // the RLIMIT_DATA resource limit, which is used by the sandbox. So, while
-  // this change costs 0 physical memory (and actually saves some, by reducing
-  // the size of the VMA red-black tree in the kernel), it might increase
-  // slightly the cases where we bump into the sandbox memory limit.
-  //
-  // Is it safe to do while running?
-  // Since this is decided through root settings, the value changes at runtime,
-  // so we may decommit memory that was never committed. This is safe onLinux,
-  // since decommitting is just changing permissions back to PROT_NONE, which
-  // the tail end would already have.
-  //
-  // Can we do better?
-  // For simplicity, we do not "fix" the regions that were committed before the
-  // settings are changed (after feature list initialization). This means that
-  // we end up with more regions that we could. The intent is to run a field
-  // experiment, then change the default value, at which point we get the full
-  // impact, so this is only temporary.
-  return root->settings.fewer_memory_regions
-             ? (get_pages_per_slot_span() << PartitionPageShift())
-             : get_bytes_per_span();
-}
-
 }  // namespace partition_alloc::internal
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_bucket.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_bucket.h
@ -1,6 +1,7 @@
 // Copyright 2018 The Chromium Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
+
 #ifndef PARTITION_ALLOC_PARTITION_BUCKET_H_
 #define PARTITION_ALLOC_PARTITION_BUCKET_H_

@ -170,8 +171,6 @@ struct PartitionBucket {
      SlotSpanMetadata<MetadataKind::kReadOnly>* slot_span,
      PartitionRoot* root);

-  size_t SlotSpanCommittedSize(PartitionRoot* root) const;
-
 private:
  // Sets `this->can_store_raw_size`.
  void InitCanStoreRawSize(bool use_small_single_slot_spans);
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_page.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_page.cc
@ -248,7 +248,7 @@ void SlotSpanMetadata<MetadataKind::kWritable>::Decommit(PartitionRoot* root) {
  size_t dirty_size =
      base::bits::AlignUp(GetProvisionedSize(), SystemPageSize());
  size_t size_to_decommit =
-      kUseLazyCommit ? dirty_size : bucket->SlotSpanCommittedSize(root);
+      kUseLazyCommit ? dirty_size : bucket->get_bytes_per_span();

  PA_DCHECK(root->empty_slot_spans_dirty_bytes >= dirty_size);
  root->empty_slot_spans_dirty_bytes -= dirty_size;
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_page.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_page.h
@ -938,7 +938,8 @@ PA_ALWAYS_INLINE void SlotSpanMetadata<MetadataKind::kWritable>::Reset() {
 // Iterates over all slot spans in a super-page. |Callback| must return true if
 // early return is needed.
 template <typename Callback>
-void IterateSlotSpans(uintptr_t super_page, Callback callback) {
+void IterateSlotSpans(uintptr_t super_page,
+                      Callback callback) {
 #if PA_BUILDFLAG(DCHECKS_ARE_ON)
  PA_DCHECK(!(super_page % kSuperPageAlignment));
  auto* extent_entry = PartitionSuperPageToExtent(super_page);
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_page_constants.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_page_constants.h
@ -17,7 +17,7 @@ namespace partition_alloc::internal {
 // PartitionPageSize() is 4 times the OS page size.
 static constexpr size_t kMaxSlotsPerSlotSpan = 4 * (1 << 14) / kSmallestBucket;
 #elif defined(PARTITION_ALLOCATOR_CONSTANTS_POSIX_NONCONST_PAGE_SIZE) && \
-    PA_BUILDFLAG(IS_LINUX) &&                                            \
+    PA_BUILDFLAG(IS_LINUX) && \
    (PA_BUILDFLAG(PA_ARCH_CPU_ARM64) || PA_BUILDFLAG(PA_ARCH_CPU_PPC64))
 // System page size can be 4, 16, or 64 kiB on Linux on AArch64.
 // System page size can be 4 or 64 kiB on Linux on ppc64.
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_root.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_root.cc
@ -51,10 +51,6 @@
 #endif  // PA_CONFIG(ENABLE_SHADOW_METADATA)
 #endif  // PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)

-#if defined(__MUSL__)
-#include "partition_alloc/shim/allocator_shim.h"
-#endif
-
 namespace partition_alloc::internal {

 #if PA_BUILDFLAG(RECORD_ALLOC_INFO)
@ -109,10 +105,6 @@ PtrPosWithinAlloc IsPtrWithinSameAlloc(uintptr_t orig_address,

 namespace partition_alloc {

-#if PA_CONFIG(ENABLE_SHADOW_METADATA)
-internal::SharedMutex PartitionRoot::g_shadow_metadata_init_mutex_;
-#endif  // PA_CONFIG(ENABLE_SHADOW_METADATA)
-
 #if PA_CONFIG(USE_PARTITION_ROOT_ENUMERATOR)

 namespace {
@ -301,7 +293,12 @@ void PartitionAllocMallocInitOnce() {
    return;
  }

-#if PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)
+#if defined(__MUSL__)
+  // Musl calls malloc() in pthread_atfork(), resulting in a deadlock.
+  static_cast<void>(BeforeForkInParent);
+  static_cast<void>(AfterForkInParent);
+  static_cast<void>(AfterForkInChild);
+#elif PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)
  // When fork() is called, only the current thread continues to execute in the
  // child process. If the lock is held, but *not* by this thread when fork() is
  // called, we have a deadlock.
@ -323,25 +320,9 @@ void PartitionAllocMallocInitOnce() {
  // However, no perfect solution really exists to make threads + fork()
  // cooperate, but deadlocks are real (and fork() is used in DEATH_TEST()s),
  // and other malloc() implementations use the same techniques.
-
-#if defined(__MUSL__)
-    allocator_shim::AllocatorDispatch d =
-        *allocator_shim::GetAllocatorDispatchChainHeadForTesting();
-    d.alloc_function = +[](size_t size, void*) -> void* {
-      // The size of the scratch fits struct atfork_funcs in Musl pthread_atfork.c.
-      static char scratch[5 * sizeof(void*)];
-      return size != sizeof(scratch) ? nullptr : scratch;
-    };
-    allocator_shim::InsertAllocatorDispatch(&d);
-#endif
-
  int err =
      pthread_atfork(BeforeForkInParent, AfterForkInParent, AfterForkInChild);
  PA_CHECK(err == 0);
-
-#if defined(__MUSL__)
-    allocator_shim::RemoveAllocatorDispatchForTesting(&d);
-#endif
 #endif  // PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)
 }

@ -1174,8 +1155,6 @@ void PartitionRoot::Init(PartitionOptions opts) {
        opts.zapping_by_free_flags == PartitionOptions::kEnabled;
    settings.eventually_zero_freed_memory =
        opts.eventually_zero_freed_memory == PartitionOptions::kEnabled;
-    settings.fewer_memory_regions =
-        opts.fewer_memory_regions == PartitionOptions::kEnabled;

    settings.scheduler_loop_quarantine =
        opts.scheduler_loop_quarantine == PartitionOptions::kEnabled;
@ -1240,7 +1219,6 @@ void PartitionRoot::Init(PartitionOptions opts) {
    if (brp_enabled()) {
      settings.in_slot_metadata_size = internal::kInSlotMetadataSizeAdjustment;
      settings.extras_size += internal::kInSlotMetadataSizeAdjustment;
-      settings.extras_size += opts.backup_ref_ptr_extra_extras_size;
 #if PA_CONFIG(MAYBE_ENABLE_MAC11_MALLOC_SIZE_HACK)
      EnableMac11MallocSizeHackIfNeeded();
 #endif
@ -1374,9 +1352,6 @@ void PartitionRoot::EnableThreadCacheIfSupported() {
      thread_caches_being_constructed_.fetch_add(1, std::memory_order_acquire);
  PA_CHECK(before == 0);
  ThreadCache::Init(this);
-  // Create thread cache for this thread so that we can start using it right
-  // after.
-  ThreadCache::Create(this);
  thread_caches_being_constructed_.fetch_sub(1, std::memory_order_release);
  settings.with_thread_cache = true;
 #endif  // PA_CONFIG(THREAD_CACHE_SUPPORTED)
@ -1996,7 +1971,6 @@ void PartitionRoot::EnableShadowMetadata(internal::PoolHandleMask mask) {
  // This is required to enable ShadowMetadata on utility processes.
  { close(memfd_create("module_cache", MFD_CLOEXEC)); }
 #endif
-  internal::UniqueLock unique_lock(g_shadow_metadata_init_mutex_);

  internal::ScopedGuard guard(g_root_enumerator_lock);
  // Must lock all PartitionRoot-s and ThreadCache.
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_root.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_root.h
@ -71,7 +71,6 @@
 #include "partition_alloc/partition_lock.h"
 #include "partition_alloc/partition_oom.h"
 #include "partition_alloc/partition_page.h"
-#include "partition_alloc/partition_shared_mutex.h"
 #include "partition_alloc/reservation_offset_table.h"
 #include "partition_alloc/tagging.h"
 #include "partition_alloc/thread_cache.h"
@ -166,12 +165,10 @@ struct PartitionOptions {
  static constexpr auto kEnabled = EnableToggle::kEnabled;

  EnableToggle thread_cache = kDisabled;
+  AllowToggle star_scan_quarantine = kDisallowed;
  EnableToggle backup_ref_ptr = kDisabled;
  AllowToggle use_configurable_pool = kDisallowed;

-  // TODO(https://crbug.com/371135823): Remove after the investigation.
-  size_t backup_ref_ptr_extra_extras_size = 0;
-
  EnableToggle scheduler_loop_quarantine = kDisabled;
  size_t scheduler_loop_quarantine_branch_capacity_in_bytes = 0;

@ -182,7 +179,6 @@ struct PartitionOptions {
  // compression ratio of freed memory inside partially allocated pages (due to
  // fragmentation).
  EnableToggle eventually_zero_freed_memory = kDisabled;
-  EnableToggle fewer_memory_regions = kDisabled;

  struct {
    EnableToggle enabled = kDisabled;
@ -262,14 +258,9 @@ struct alignas(64) PA_COMPONENT_EXPORT(PARTITION_ALLOC) PartitionRoot {
    size_t in_slot_metadata_size = 0;
 #endif  // PA_BUILDFLAG(ENABLE_BACKUP_REF_PTR_SUPPORT)
    bool use_configurable_pool = false;
-    // Despite its name, `FreeFlags` for zapping is deleted and does not exist.
-    // This value is used for SchedulerLoopQuarantine.
-    // TODO(https://crbug.com/351974425): group this setting and quarantine
-    // setting in one place.
    bool zapping_by_free_flags = false;
    bool eventually_zero_freed_memory = false;
    bool scheduler_loop_quarantine = false;
-    bool fewer_memory_regions = false;
 #if PA_BUILDFLAG(HAS_MEMORY_TAGGING)
    bool memory_tagging_enabled_ = false;
    bool use_random_memory_tagging_ = false;
@ -396,12 +387,6 @@ struct alignas(64) PA_COMPONENT_EXPORT(PARTITION_ALLOC) PartitionRoot {
  internal::base::TimeTicks (*now_maybe_overridden_for_testing)() =
      internal::base::TimeTicks::Now;

-#if PA_CONFIG(ENABLE_SHADOW_METADATA)
-  // Locks not to run EnableShadowMetadata() and PartitionDirectMap()
-  // at the same time.
-  static internal::SharedMutex g_shadow_metadata_init_mutex_;
-#endif  // PA_CONFIG(ENABLE_SHADOW_METADATA)
-
  PartitionRoot();
  explicit PartitionRoot(PartitionOptions opts);

@ -899,14 +884,6 @@ struct alignas(64) PA_COMPONENT_EXPORT(PARTITION_ALLOC) PartitionRoot {
    return GetSchedulerLoopQuarantineBranch();
  }

-  void SetSchedulerLoopQuarantineThreadLocalBranchCapacity(
-      size_t capacity_in_bytes) {
-    ThreadCache* thread_cache = this->GetOrCreateThreadCache();
-    PA_CHECK(ThreadCache::IsValid(thread_cache));
-    thread_cache->GetSchedulerLoopQuarantineBranch().SetCapacityInBytes(
-        capacity_in_bytes);
-  }
-
  const internal::PartitionFreelistDispatcher* get_freelist_dispatcher() {
 #if PA_BUILDFLAG(USE_FREELIST_DISPATCHER)
    if (settings.use_pool_offset_freelists) {
@ -1522,11 +1499,16 @@ PA_ALWAYS_INLINE void PartitionRoot::FreeInline(void* object) {
  // cacheline ping-pong.
  PA_PREFETCH(slot_span);

-  // TODO(crbug.com/40287058): Collecting objects for
-  // `kSchedulerLoopQuarantineBranch` here means it "delays" other checks (BRP
-  // refcount, cookie, etc.)
-  // For better debuggability, we should do these checks before quarantining.
-  if constexpr (ContainsFlags(flags, FreeFlags::kSchedulerLoopQuarantine)) {
+  // Further down, we may zap the memory, no point in doing it twice.  We may
+  // zap twice if kZap is enabled without kSchedulerLoopQuarantine. Make sure it
+  // does not happen. This is not a hard requirement: if this is deemed cheap
+  // enough, it can be relaxed, the static_assert() is here to make it a
+  // conscious decision.
+  static_assert(!ContainsFlags(flags, FreeFlags::kZap) ||
+                    ContainsFlags(flags, FreeFlags::kSchedulerLoopQuarantine),
+                "kZap and kSchedulerLoopQuarantine should be used together to "
+                "avoid double zapping");
+  if constexpr (ContainsFlags(flags, FreeFlags::kZap)) {
    // No need to zap direct mapped allocations, as they are unmapped right
    // away. This also ensures that we don't needlessly memset() very large
    // allocations.
@ -1535,7 +1517,12 @@ PA_ALWAYS_INLINE void PartitionRoot::FreeInline(void* object) {
      internal::SecureMemset(object, internal::kFreedByte,
                             GetSlotUsableSize(slot_span));
    }
-
+  }
+  // TODO(crbug.com/40287058): Collecting objects for
+  // `kSchedulerLoopQuarantineBranch` here means it "delays" other checks (BRP
+  // refcount, cookie, etc.)
+  // For better debuggability, we should do these checks before quarantining.
+  if constexpr (ContainsFlags(flags, FreeFlags::kSchedulerLoopQuarantine)) {
    if (settings.scheduler_loop_quarantine) {
 #if PA_BUILDFLAG(ENABLE_BACKUP_REF_PTR_SUPPORT)
      // TODO(keishi): Add `[[likely]]` when brp is fully enabled as
@ -2478,7 +2465,7 @@ void* PartitionRoot::ReallocInline(void* ptr,
  constexpr bool no_hooks = ContainsFlags(alloc_flags, AllocFlags::kNoHooks);
  const bool hooks_enabled = PartitionAllocHooks::AreHooksEnabled();
  bool overridden = false;
-  size_t old_usable_size = 0;
+  size_t old_usable_size;
  if (!no_hooks && hooks_enabled) [[unlikely]] {
    overridden = PartitionAllocHooks::ReallocOverrideHookIfEnabled(
        &old_usable_size, ptr);
@ -2521,21 +2508,6 @@ void* PartitionRoot::ReallocInline(void* ptr,
    }
  }

-#if PA_BUILDFLAG(REALLOC_GROWTH_FACTOR_MITIGATION)
-  // Some nVidia drivers have a performance bug where they repeatedly realloc a
-  // buffer with a small 4144 byte increment instead of using a growth factor to
-  // amortize the cost of a memcpy. To work around this, we apply a growth
-  // factor to the new size to avoid this issue. This workaround is only
-  // intended to be used for Skia bots, and is not intended to be a general
-  // solution.
-  if (new_size > old_usable_size && new_size > 12 << 20) {
-    // 1.5x growth factor.
-    // Note that in case of integer overflow, the std::max ensures that the
-    // new_size is at least as large as the old_usable_size.
-    new_size = std::max(new_size, old_usable_size * 3 / 2);
-  }
-#endif
-
  // This realloc cannot be resized in-place. Sadness.
  void* ret = AllocInternal<alloc_flags>(
      new_size, internal::PartitionPageSize(), type_name);
--- a/src/base/allocator/partition_allocator/src/partition_alloc/partition_shared_mutex.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/partition_shared_mutex.h
@ -1,82 +0,0 @@
-// Copyright 2024 The Chromium Authors
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef PARTITION_ALLOC_PARTITION_SHARED_MUTEX_H_
-#define PARTITION_ALLOC_PARTITION_SHARED_MUTEX_H_
-
-#include "partition_alloc/partition_alloc_base/thread_annotations.h"
-#include "partition_alloc/partition_lock.h"
-
-namespace partition_alloc::internal {
-
-// A partial implementation of `std::shared_mutex` for PartitionAllocator.
-// Since `std::shared_mutex` allocates memory, we cannot use it inside
-// PartitionAllocator. The difference between `std::shared_mutex` and this
-// SharedMutex, this SharedMutex doesn't support try_lock() and
-// try_lock_shared(), because no code uses the methods.
-class PA_LOCKABLE SharedMutex {
- public:
-  inline constexpr SharedMutex() = default;
-
-  void lock() PA_EXCLUSIVE_LOCK_FUNCTION() { writer_lock_.Acquire(); }
-
-  void unlock() PA_UNLOCK_FUNCTION() { writer_lock_.Release(); }
-
-  void lock_shared() PA_SHARED_LOCK_FUNCTION() {
-    ScopedGuard lock(reader_lock_);
-    ++counter_;
-    if (counter_ == 1u) {
-      writer_lock_.Acquire();
-    }
-  }
-
-  void unlock_shared() PA_UNLOCK_FUNCTION() {
-    ScopedGuard lock(reader_lock_);
-    --counter_;
-    if (counter_ == 0u) {
-      writer_lock_.Release();
-    }
-  }
-
- private:
-  Lock reader_lock_;
-  Lock writer_lock_;
-  size_t counter_ PA_GUARDED_BY(reader_lock_) = 0;
-};
-
-static_assert(std::is_trivially_destructible_v<SharedMutex>,
-              "SharedMutex must be trivally destructible.");
-
-// A partial implementation of `std::unique_lock` for PartitionAllocator.
-// Locking a UniqueLock locks the associated shared mutex in exclusive mode.
-class PA_SCOPED_LOCKABLE UniqueLock {
- public:
-  explicit UniqueLock(SharedMutex& mutex) PA_EXCLUSIVE_LOCK_FUNCTION(mutex)
-      : mutex_(mutex) {
-    mutex_.lock();
-  }
-  ~UniqueLock() PA_UNLOCK_FUNCTION() { mutex_.unlock(); }
-
- private:
-  SharedMutex& mutex_;
-};
-
-// A partial implementation of `std::shared_lock` for PartitionAllocator.
-// Locking a SharedLock locks the associated shared mutex in shared mode.
-// (like std::shared_lock).
-class PA_SCOPED_LOCKABLE SharedLock {
- public:
-  explicit SharedLock(SharedMutex& mutex) PA_SHARED_LOCK_FUNCTION(mutex)
-      : mutex_(mutex) {
-    mutex_.lock_shared();
-  }
-  ~SharedLock() PA_UNLOCK_FUNCTION() { mutex_.unlock_shared(); }
-
- private:
-  SharedMutex& mutex_;
-};
-
-}  // namespace partition_alloc::internal
-
-#endif  // PARTITION_ALLOC_PARTITION_SHARED_MUTEX_H_
--- a/src/base/allocator/partition_allocator/src/partition_alloc/pointers/raw_ptr.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/pointers/raw_ptr.h
@ -10,8 +10,6 @@
 #include <cstddef>
 #include <cstdint>
 #include <functional>
-#include <iterator>
-#include <memory>
 #include <type_traits>
 #include <utility>

@ -22,7 +20,6 @@
 #include "partition_alloc/partition_alloc_base/compiler_specific.h"
 #include "partition_alloc/partition_alloc_base/component_export.h"
 #include "partition_alloc/partition_alloc_base/cxx20_is_constant_evaluated.h"
-#include "partition_alloc/partition_alloc_base/types/same_as_any.h"
 #include "partition_alloc/partition_alloc_config.h"
 #include "partition_alloc/partition_alloc_forward.h"
 #include "partition_alloc/pointers/instance_tracer.h"
@ -72,7 +69,7 @@ class TextureLayerImpl;
 namespace base::internal {
 class DelayTimerBase;
 class JobTaskSource;
-}  // namespace base::internal
+}
 namespace base::test {
 struct RawPtrCountingImplForTest;
 }
@ -178,29 +175,84 @@ namespace raw_ptr_traits {
 // that raw_ptr is not used with unsupported types. As an example, see how
 // base::internal::Unretained(Ref)Wrapper uses IsSupportedType to decide whether
 // it should use `raw_ptr<T>` or `T*`.
-template <typename T>
+template <typename T, typename SFINAE = void>
 struct IsSupportedType {
-  static constexpr bool value =
-      // raw_ptr<T> is not compatible with function pointer types. Also, they
-      // don't even need the raw_ptr protection, because they don't point on
-      // heap.
-      !std::is_function_v<T> &&
+  static constexpr bool value = true;
+};
+
+// raw_ptr<T> is not compatible with function pointer types. Also, they don't
+// even need the raw_ptr protection, because they don't point on heap.
+template <typename T>
+struct IsSupportedType<T, std::enable_if_t<std::is_function_v<T>>> {
+  static constexpr bool value = false;
+};
+
+// This section excludes some types from raw_ptr<T> to avoid them from being
+// used inside base::Unretained in performance sensitive places.
+// The ones below were identified from sampling profiler data. See
+// crbug.com/1287151 for more info.
+template <>
+struct IsSupportedType<cc::Scheduler> {
+  static constexpr bool value = false;
+};
+template <>
+struct IsSupportedType<base::internal::DelayTimerBase> {
+  static constexpr bool value = false;
+};
+template <>
+struct IsSupportedType<content::responsiveness::Calculator> {
+  static constexpr bool value = false;
+};
+// The ones below were identified from speedometer3. See crbug.com/335556942 for
+// more info.
+template <>
+struct IsSupportedType<v8::JobTask> {
+  static constexpr bool value = false;
+};
+template <>
+struct IsSupportedType<blink::scheduler::MainThreadTaskQueue> {
+  static constexpr bool value = false;
+};
+template <>
+struct IsSupportedType<base::sequence_manager::internal::TaskQueueImpl> {
+  static constexpr bool value = false;
+};
+template <>
+struct IsSupportedType<base::internal::JobTaskSource> {
+  static constexpr bool value = false;
+};
+template <>
+struct IsSupportedType<mojo::Connector> {
+  static constexpr bool value = false;
+};
+template <>
+struct IsSupportedType<blink::scheduler::NonMainThreadTaskQueue> {
+  static constexpr bool value = false;
+};
+// The ones below were identified from MotionMark. See crbug.com/335556942 for
+// more info.
+template <>
+struct IsSupportedType<cc::ImageDecodeCache> {
+  static constexpr bool value = false;
+};
+template <>
+struct IsSupportedType<cc::TextureLayerImpl> {
+  static constexpr bool value = false;
+};

 #if __OBJC__
-      // raw_ptr<T> is not compatible with pointers to Objective-C classes for a
-      // multitude of reasons. They may fail to compile in many cases, and
-      // wouldn't work well with tagged pointers. Anyway, Objective-C objects
-      // have their own way of tracking lifespan, hence don't need the raw_ptr
-      // protection as much.
-      //
-      // Such pointers are detected by checking if they're convertible to |id|
-      // type.
-      !std::is_convertible_v<T*, id> &&
+// raw_ptr<T> is not compatible with pointers to Objective-C classes for a
+// multitude of reasons. They may fail to compile in many cases, and wouldn't
+// work well with tagged pointers. Anyway, Objective-C objects have their own
+// way of tracking lifespan, hence don't need the raw_ptr protection as much.
+//
+// Such pointers are detected by checking if they're convertible to |id| type.
+template <typename T>
+struct IsSupportedType<T, std::enable_if_t<std::is_convertible_v<T*, id>>> {
+  static constexpr bool value = false;
+};
 #endif  // __OBJC__

-      // Specific disallowed types.
-      !partition_alloc::internal::base::kSameAsAny<
-          T,
 #if PA_BUILDFLAG(IS_WIN)
 // raw_ptr<HWND__> is unsafe at runtime - if the handle happens to also
 // represent a valid pointer into a PartitionAlloc-managed region then it can
@ -216,30 +268,14 @@ struct IsSupportedType {
 // upside of this approach is that it will safely handle base::Bind closing over
 // HANDLE.  The downside of this approach is that base::Bind closing over a
 // void* pointer will not get UaF protection.
-#define PA_WINDOWS_HANDLE_TYPE(name) name##__,
+#define PA_WINDOWS_HANDLE_TYPE(name)       \
+  template <>                              \
+  struct IsSupportedType<name##__, void> { \
+    static constexpr bool value = false;   \
+  };
 #include "partition_alloc/partition_alloc_base/win/win_handle_types_list.inc"
 #undef PA_WINDOWS_HANDLE_TYPE
 #endif
-          // Performance-sensitive types identified via sampling profiler data;
-          // see crbug.com/1287151
-          base::internal::DelayTimerBase,
-          cc::Scheduler,
-          content::responsiveness::Calculator,
-
-          // Performance-sensitive types identified via speedometer3; see
-          // crbug.com/335556942
-          base::internal::JobTaskSource,
-          base::sequence_manager::internal::TaskQueueImpl,
-          blink::scheduler::MainThreadTaskQueue,
-          blink::scheduler::NonMainThreadTaskQueue,
-          mojo::Connector,
-          v8::JobTask,
-
-          // Performance-sensitive types identified via MotionMark; see
-          // crbug.com/335556942
-          cc::ImageDecodeCache,
-          cc::TextureLayerImpl>;
-};

 #if PA_BUILDFLAG(USE_RAW_PTR_BACKUP_REF_IMPL)
 template <RawPtrTraits Traits>
@ -1066,32 +1102,51 @@ PA_ALWAYS_INLINE constexpr bool operator>=(const raw_ptr<U, Traits1>& lhs,
 #endif

 template <typename T>
-inline constexpr bool IsRawPtr = false;
+struct IsRawPtr : std::false_type {};
+
 template <typename T, RawPtrTraits Traits>
-inline constexpr bool IsRawPtr<raw_ptr<T, Traits>> = true;
+struct IsRawPtr<raw_ptr<T, Traits>> : std::true_type {};

 template <typename T>
-inline constexpr bool IsRawPtrMayDangle = false;
+inline constexpr bool IsRawPtrV = IsRawPtr<T>::value;
+
+template <typename T>
+inline constexpr bool IsRawPtrMayDangleV = false;
+
 template <typename T, RawPtrTraits Traits>
-inline constexpr bool IsRawPtrMayDangle<raw_ptr<T, Traits>> =
+inline constexpr bool IsRawPtrMayDangleV<raw_ptr<T, Traits>> =
    partition_alloc::internal::ContainsFlags(Traits, RawPtrTraits::kMayDangle);

+// Template helpers for working with T* or raw_ptr<T>.
 template <typename T>
-inline constexpr bool IsPointerOrRawPtr = std::is_pointer_v<T>;
-template <typename T, RawPtrTraits Traits>
-inline constexpr bool IsPointerOrRawPtr<raw_ptr<T, Traits>> = true;
+struct IsRawPointerHelper : std::false_type {};

-// Like `std::remove_pointer_t<>`, but also converts `raw_ptr<T>` => `T`.
 template <typename T>
-struct RemovePointer {
-  using type = std::remove_pointer_t<T>;
-};
+struct IsRawPointerHelper<T*> : std::true_type {};
+
 template <typename T, RawPtrTraits Traits>
-struct RemovePointer<raw_ptr<T, Traits>> {
+struct IsRawPointerHelper<raw_ptr<T, Traits>> : std::true_type {};
+
+template <typename T>
+inline constexpr bool IsRawPointer = IsRawPointerHelper<T>::value;
+
+template <typename T>
+struct RemoveRawPointer {
  using type = T;
 };
+
 template <typename T>
-using RemovePointerT = typename RemovePointer<T>::type;
+struct RemoveRawPointer<T*> {
+  using type = T;
+};
+
+template <typename T, RawPtrTraits Traits>
+struct RemoveRawPointer<raw_ptr<T, Traits>> {
+  using type = T;
+};
+
+template <typename T>
+using RemoveRawPointerT = typename RemoveRawPointer<T>::type;

 }  // namespace base

@ -1255,34 +1310,6 @@ struct pointer_traits<::raw_ptr<T, Traits>> {
  }
 };

-#if PA_BUILDFLAG(ASSERT_CPP_20)
-// Mark `raw_ptr<T>` and `T*` as having a common reference type (the type to
-// which both can be converted or bound) of `T*`. This makes them satisfy
-// `std::equality_comparable`, which allows usage like:
-// ```
-//   std::vector<raw_ptr<T>> v;
-//   T* e;
-//   auto it = std::ranges::find(v, e);
-// ```
-// Without this, the `find()` call above would fail to compile with a cryptic
-// error about being unable to invoke `std::ranges::equal_to()`.
-template <typename T,
-          base::RawPtrTraits Traits,
-          template <typename> typename TQ,
-          template <typename> typename UQ>
-struct basic_common_reference<raw_ptr<T, Traits>, T*, TQ, UQ> {
-  using type = T*;
-};
-
-template <typename T,
-          base::RawPtrTraits Traits,
-          template <typename> typename TQ,
-          template <typename> typename UQ>
-struct basic_common_reference<T*, raw_ptr<T, Traits>, TQ, UQ> {
-  using type = T*;
-};
-#endif  // PA_BUILDFLAG(ASSERT_CPP_20)
-
 }  // namespace std

 #endif  // PARTITION_ALLOC_POINTERS_RAW_PTR_H_
--- a/src/base/allocator/partition_allocator/src/partition_alloc/pointers/raw_ptr_asan_unowned_impl.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/pointers/raw_ptr_asan_unowned_impl.cc
@ -5,7 +5,6 @@
 #include "partition_alloc/pointers/raw_ptr_asan_unowned_impl.h"

 #include <sanitizer/asan_interface.h>
-
 #include <cstdint>

 #include "partition_alloc/partition_alloc_base/compiler_specific.h"
--- a/src/base/allocator/partition_allocator/src/partition_alloc/pointers/raw_ref.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/pointers/raw_ref.h
@ -26,10 +26,18 @@ namespace base {
 template <class T, RawPtrTraits Traits>
 class raw_ref;

+namespace internal {
+
 template <class T>
-inline constexpr bool IsRawRef = false;
+struct is_raw_ref : std::false_type {};
+
 template <class T, RawPtrTraits Traits>
-inline constexpr bool IsRawRef<::base::raw_ref<T, Traits>> = true;
+struct is_raw_ref<::base::raw_ref<T, Traits>> : std::true_type {};
+
+template <class T>
+constexpr inline bool is_raw_ref_v = is_raw_ref<T>::value;
+
+}  // namespace internal

 // A smart pointer for a pointer which can not be null, and which provides
 // Use-after-Free protection in the same ways as raw_ptr. This class acts like a
@ -248,25 +256,25 @@ class PA_TRIVIAL_ABI PA_GSL_POINTER raw_ref {
                                   const raw_ref<V, Traits2>& rhs);
 #endif

-  template <class U, class = std::enable_if_t<!IsRawRef<U>, void>>
+  template <class U, class = std::enable_if_t<!internal::is_raw_ref_v<U>, void>>
  PA_ALWAYS_INLINE friend constexpr bool operator==(const raw_ref& lhs,
                                                    const U& rhs) {
    PA_RAW_PTR_CHECK(lhs.inner_);  // Catch use-after-move.
    return lhs.inner_ == &rhs;
  }
-  template <class U, class = std::enable_if_t<!IsRawRef<U>, void>>
+  template <class U, class = std::enable_if_t<!internal::is_raw_ref_v<U>, void>>
  PA_ALWAYS_INLINE friend constexpr bool operator!=(const raw_ref& lhs,
                                                    const U& rhs) {
    PA_RAW_PTR_CHECK(lhs.inner_);  // Catch use-after-move.
    return lhs.inner_ != &rhs;
  }
-  template <class U, class = std::enable_if_t<!IsRawRef<U>, void>>
+  template <class U, class = std::enable_if_t<!internal::is_raw_ref_v<U>, void>>
  PA_ALWAYS_INLINE friend constexpr bool operator==(const U& lhs,
                                                    const raw_ref& rhs) {
    PA_RAW_PTR_CHECK(rhs.inner_);  // Catch use-after-move.
    return &lhs == rhs.inner_;
  }
-  template <class U, class = std::enable_if_t<!IsRawRef<U>, void>>
+  template <class U, class = std::enable_if_t<!internal::is_raw_ref_v<U>, void>>
  PA_ALWAYS_INLINE friend constexpr bool operator!=(const U& lhs,
                                                    const raw_ref& rhs) {
    PA_RAW_PTR_CHECK(rhs.inner_);  // Catch use-after-move.
@ -274,62 +282,62 @@ class PA_TRIVIAL_ABI PA_GSL_POINTER raw_ref {
  }

 #if PA_HAVE_SPACESHIP_OPERATOR
-  template <class U, class = std::enable_if_t<!IsRawRef<U>, void>>
+  template <class U, class = std::enable_if_t<!internal::is_raw_ref_v<U>, void>>
  PA_ALWAYS_INLINE friend constexpr auto operator<=>(const raw_ref& lhs,
                                                     const U& rhs) {
    PA_RAW_PTR_CHECK(lhs.inner_);  // Catch use-after-move.
    return lhs.inner_ <=> &rhs;
  }
-  template <class U, class = std::enable_if_t<!IsRawRef<U>, void>>
+  template <class U, class = std::enable_if_t<!internal::is_raw_ref_v<U>, void>>
  PA_ALWAYS_INLINE friend constexpr auto operator<=>(const U& lhs,
                                                     const raw_ref& rhs) {
    PA_RAW_PTR_CHECK(rhs.inner_);  // Catch use-after-move.
    return &lhs <=> rhs.inner_;
  }
 #else
-  template <class U, class = std::enable_if_t<!IsRawRef<U>, void>>
+  template <class U, class = std::enable_if_t<!internal::is_raw_ref_v<U>, void>>
  PA_ALWAYS_INLINE friend constexpr bool operator<(const raw_ref& lhs,
                                                   const U& rhs) {
    PA_RAW_PTR_CHECK(lhs.inner_);  // Catch use-after-move.
    return lhs.inner_ < &rhs;
  }
-  template <class U, class = std::enable_if_t<!IsRawRef<U>, void>>
+  template <class U, class = std::enable_if_t<!internal::is_raw_ref_v<U>, void>>
  PA_ALWAYS_INLINE friend constexpr bool operator>(const raw_ref& lhs,
                                                   const U& rhs) {
    PA_RAW_PTR_CHECK(lhs.inner_);  // Catch use-after-move.
    return lhs.inner_ > &rhs;
  }
-  template <class U, class = std::enable_if_t<!IsRawRef<U>, void>>
+  template <class U, class = std::enable_if_t<!internal::is_raw_ref_v<U>, void>>
  PA_ALWAYS_INLINE friend constexpr bool operator<=(const raw_ref& lhs,
                                                    const U& rhs) {
    PA_RAW_PTR_CHECK(lhs.inner_);  // Catch use-after-move.
    return lhs.inner_ <= &rhs;
  }
-  template <class U, class = std::enable_if_t<!IsRawRef<U>, void>>
+  template <class U, class = std::enable_if_t<!internal::is_raw_ref_v<U>, void>>
  PA_ALWAYS_INLINE friend constexpr bool operator>=(const raw_ref& lhs,
                                                    const U& rhs) {
    PA_RAW_PTR_CHECK(lhs.inner_);  // Catch use-after-move.
    return lhs.inner_ >= &rhs;
  }
-  template <class U, class = std::enable_if_t<!IsRawRef<U>, void>>
+  template <class U, class = std::enable_if_t<!internal::is_raw_ref_v<U>, void>>
  PA_ALWAYS_INLINE friend constexpr bool operator<(const U& lhs,
                                                   const raw_ref& rhs) {
    PA_RAW_PTR_CHECK(rhs.inner_);  // Catch use-after-move.
    return &lhs < rhs.inner_;
  }
-  template <class U, class = std::enable_if_t<!IsRawRef<U>, void>>
+  template <class U, class = std::enable_if_t<!internal::is_raw_ref_v<U>, void>>
  PA_ALWAYS_INLINE friend constexpr bool operator>(const U& lhs,
                                                   const raw_ref& rhs) {
    PA_RAW_PTR_CHECK(rhs.inner_);  // Catch use-after-move.
    return &lhs > rhs.inner_;
  }
-  template <class U, class = std::enable_if_t<!IsRawRef<U>, void>>
+  template <class U, class = std::enable_if_t<!internal::is_raw_ref_v<U>, void>>
  PA_ALWAYS_INLINE friend constexpr bool operator<=(const U& lhs,
                                                    const raw_ref& rhs) {
    PA_RAW_PTR_CHECK(rhs.inner_);  // Catch use-after-move.
    return &lhs <= rhs.inner_;
  }
-  template <class U, class = std::enable_if_t<!IsRawRef<U>, void>>
+  template <class U, class = std::enable_if_t<!internal::is_raw_ref_v<U>, void>>
  PA_ALWAYS_INLINE friend constexpr bool operator>=(const U& lhs,
                                                    const raw_ref& rhs) {
    PA_RAW_PTR_CHECK(rhs.inner_);  // Catch use-after-move.
@ -403,15 +411,26 @@ raw_ref(T&) -> raw_ref<T>;
 template <class T>
 raw_ref(const T&) -> raw_ref<const T>;

-// Converts `raw_ref<T>` => `T`; leaves l/rvalue refs alone.
+// Template helpers for working with raw_ref<T>.
+template <typename T>
+struct IsRawRef : std::false_type {};
+
+template <typename T, RawPtrTraits Traits>
+struct IsRawRef<raw_ref<T, Traits>> : std::true_type {};
+
+template <typename T>
+inline constexpr bool IsRawRefV = IsRawRef<T>::value;
+
 template <typename T>
 struct RemoveRawRef {
  using type = T;
 };
+
 template <typename T, RawPtrTraits Traits>
 struct RemoveRawRef<raw_ref<T, Traits>> {
  using type = T;
 };
+
 template <typename T>
 using RemoveRawRefT = typename RemoveRawRef<T>::type;

--- a/src/base/allocator/partition_allocator/src/partition_alloc/random.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/random.cc
@ -27,7 +27,7 @@ class RandomGenerator {
  }

 private:
-  ::partition_alloc::internal::Lock lock_;
+  ::partition_alloc::internal::Lock lock_ = {};
  bool initialized_ PA_GUARDED_BY(lock_) = false;
  union {
    internal::base::InsecureRandomGenerator instance_ PA_GUARDED_BY(lock_);
--- a/src/base/allocator/partition_allocator/src/partition_alloc/reservation_offset_table.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/reservation_offset_table.h
@ -8,6 +8,7 @@
 #include <cstddef>
 #include <cstdint>
 #include <limits>
+#include <tuple>

 #include "partition_alloc/address_pool_manager.h"
 #include "partition_alloc/build_config.h"
--- a/src/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim.cc
@ -31,6 +31,7 @@
 // noexcept needs to be routed to
 // allocator_shim::internal::PartitionMallocUnchecked through the shim layer.
 #include "partition_alloc/shim/allocator_shim_override_cpp_symbols.h"
+
 #include "partition_alloc/shim/allocator_shim_override_libc_symbols.h"

 // Some glibc versions (until commit 6c444ad6e953dbdf9c7be065308a0a777)
--- a/src/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim.h
@ -150,9 +150,9 @@ using ZappingByFreeFlags =
                                                 bool>;
 using EventuallyZeroFreedMemory = partition_alloc::internal::base::
    StrongAlias<class EventuallyZeroFreedMemoryTag, bool>;
-using FewerMemoryRegions =
-    partition_alloc::internal::base::StrongAlias<class FewerMemoryRegionsTag,
-                                                 bool>;
+using UsePoolOffsetFreelists = partition_alloc::internal::base::
+    StrongAlias<class UsePoolOffsetFreelistsTag, bool>;
+
 using UseSmallSingleSlotSpans = partition_alloc::internal::base::
    StrongAlias<class UseSmallSingleSlotSpansTag, bool>;

@ -162,7 +162,6 @@ using UseSmallSingleSlotSpans = partition_alloc::internal::base::
 PA_COMPONENT_EXPORT(ALLOCATOR_SHIM)
 void ConfigurePartitions(
    EnableBrp enable_brp,
-    size_t brp_extra_extras_size,
    EnableMemoryTagging enable_memory_tagging,
    partition_alloc::TagViolationReportingMode memory_tagging_reporting_mode,
    BucketDistribution distribution,
@ -170,7 +169,7 @@ void ConfigurePartitions(
    size_t scheduler_loop_quarantine_branch_capacity_in_bytes,
    ZappingByFreeFlags zapping_by_free_flags,
    EventuallyZeroFreedMemory eventually_zero_freed_memory,
-    FewerMemoryRegions fewer_memory_regions,
+    UsePoolOffsetFreelists use_pool_offset_freelists,
    UseSmallSingleSlotSpans use_small_single_slot_spans);

 PA_COMPONENT_EXPORT(ALLOCATOR_SHIM) uint32_t GetMainPartitionRootExtrasSize();
--- a/src/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim_default_dispatch_to_glibc.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim_default_dispatch_to_glibc.cc
@ -2,9 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

-#include <dlfcn.h>
-#include <malloc.h>
-
 #include <limits>

 #include "partition_alloc/oom.h"
@ -12,6 +9,9 @@
 #include "partition_alloc/partition_alloc_base/numerics/checked_math.h"
 #include "partition_alloc/shim/allocator_shim.h"

+#include <dlfcn.h>
+#include <malloc.h>
+
 // This translation unit defines a default dispatch for the allocator shim which
 // routes allocations to libc functions.
 // The code here is strongly inspired from tcmalloc's libc_override_glibc.h.
--- a/src/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim_default_dispatch_to_partition_alloc.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim_default_dispatch_to_partition_alloc.cc
@ -26,7 +26,6 @@
 #include "partition_alloc/partition_root.h"
 #include "partition_alloc/partition_stats.h"
 #include "partition_alloc/shim/allocator_dispatch.h"
-#include "partition_alloc/shim/allocator_shim.h"
 #include "partition_alloc/shim/allocator_shim_default_dispatch_to_partition_alloc_internal.h"
 #include "partition_alloc/shim/allocator_shim_internals.h"

@ -102,7 +101,7 @@ class LeakySingleton {
    __cpp_lib_atomic_value_initialization < 201911L
  alignas(T) uint8_t instance_buffer_[sizeof(T)];
 #else
-  alignas(T) uint8_t instance_buffer_[sizeof(T)] = {};
+  alignas(T) uint8_t instance_buffer_[sizeof(T)] = {0};
 #endif
  std::atomic<bool> initialization_lock_;
 };
@ -149,6 +148,7 @@ class MainPartitionConstructor {
    // the decision to turn the thread cache on until then.
    // Also tests, such as the ThreadCache tests create a thread cache.
    opts.thread_cache = partition_alloc::PartitionOptions::kDisabled;
+    opts.star_scan_quarantine = partition_alloc::PartitionOptions::kAllowed;
    opts.backup_ref_ptr = partition_alloc::PartitionOptions::kDisabled;
    auto* new_root = new (buffer) partition_alloc::PartitionRoot(opts);

@ -571,6 +571,7 @@ template class PA_COMPONENT_EXPORT(ALLOCATOR_SHIM)
    PartitionAllocFunctionsInternal<
        partition_alloc::AllocFlags::kNoHooks,
        partition_alloc::FreeFlags::kNoHooks |
+            partition_alloc::FreeFlags::kZap |
            partition_alloc::FreeFlags::kSchedulerLoopQuarantine>;

 // static
@ -611,7 +612,6 @@ void EnablePartitionAllocMemoryReclaimer() {

 void ConfigurePartitions(
    EnableBrp enable_brp,
-    size_t brp_extra_extras_size,
    EnableMemoryTagging enable_memory_tagging,
    partition_alloc::TagViolationReportingMode memory_tagging_reporting_mode,
    BucketDistribution distribution,
@ -619,7 +619,7 @@ void ConfigurePartitions(
    size_t scheduler_loop_quarantine_branch_capacity_in_bytes,
    ZappingByFreeFlags zapping_by_free_flags,
    EventuallyZeroFreedMemory eventually_zero_freed_memory,
-    FewerMemoryRegions fewer_memory_regions,
+    UsePoolOffsetFreelists use_pool_offset_freelists,
    UseSmallSingleSlotSpans use_small_single_slot_spans) {
  // Calling Get() is actually important, even if the return value isn't
  // used, because it has a side effect of initializing the variable, if it
@ -640,10 +640,10 @@ void ConfigurePartitions(
        // another partition will have the thread cache enabled, by calling
        // EnableThreadCacheIfSupported().
        opts.thread_cache = partition_alloc::PartitionOptions::kDisabled;
+        opts.star_scan_quarantine = partition_alloc::PartitionOptions::kAllowed;
        opts.backup_ref_ptr =
            enable_brp ? partition_alloc::PartitionOptions::kEnabled
                       : partition_alloc::PartitionOptions::kDisabled;
-        opts.backup_ref_ptr_extra_extras_size = brp_extra_extras_size;
        opts.zapping_by_free_flags =
            zapping_by_free_flags
                ? partition_alloc::PartitionOptions::kEnabled
@ -652,9 +652,6 @@ void ConfigurePartitions(
            eventually_zero_freed_memory
                ? partition_alloc::PartitionOptions::kEnabled
                : partition_alloc::PartitionOptions::kDisabled;
-        opts.fewer_memory_regions =
-            fewer_memory_regions ? partition_alloc::PartitionOptions::kEnabled
-                                 : partition_alloc::PartitionOptions::kDisabled;
        opts.scheduler_loop_quarantine =
            scheduler_loop_quarantine
                ? partition_alloc::PartitionOptions::kEnabled
@ -667,7 +664,9 @@ void ConfigurePartitions(
                           : partition_alloc::PartitionOptions::kDisabled,
            .reporting_mode = memory_tagging_reporting_mode};
        opts.use_pool_offset_freelists =
-            partition_alloc::PartitionOptions::kEnabled;
+            use_pool_offset_freelists
+                ? partition_alloc::PartitionOptions::kEnabled
+                : partition_alloc::PartitionOptions::kDisabled;
        opts.use_small_single_slot_spans =
            use_small_single_slot_spans
                ? partition_alloc::PartitionOptions::kEnabled
@ -740,7 +739,7 @@ SHIM_ALWAYS_EXPORT int mallopt(int cmd, int value) __THROW {

 #endif  // !PA_BUILDFLAG(IS_APPLE) && !PA_BUILDFLAG(IS_ANDROID)

-#if defined(__MUSL__)
+#if defined(__MUSL__) 
 // Musl does not support struct mallinfo.
 #elif PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)
 SHIM_ALWAYS_EXPORT struct mallinfo mallinfo(void) __THROW {
--- a/src/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim_default_dispatch_to_partition_alloc.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim_default_dispatch_to_partition_alloc.h
@ -135,6 +135,7 @@ using PartitionAllocWithAdvancedChecksFunctions =
    PartitionAllocFunctionsInternal<
        partition_alloc::AllocFlags::kNoHooks,
        partition_alloc::FreeFlags::kNoHooks |
+            partition_alloc::FreeFlags::kZap |
            partition_alloc::FreeFlags::kSchedulerLoopQuarantine>;

 // `PartitionAllocFunctions` in instantiated in cc file.
@ -146,6 +147,7 @@ extern template class PA_COMPONENT_EXPORT(ALLOCATOR_SHIM)
    PartitionAllocFunctionsInternal<
        partition_alloc::AllocFlags::kNoHooks,
        partition_alloc::FreeFlags::kNoHooks |
+            partition_alloc::FreeFlags::kZap |
            partition_alloc::FreeFlags::kSchedulerLoopQuarantine>;

 }  // namespace internal
@ -162,7 +164,6 @@ extern template class PA_COMPONENT_EXPORT(ALLOCATOR_SHIM)
 // this function. They should call ConfigurePartitions() directly.
 PA_ALWAYS_INLINE void ConfigurePartitionsForTesting() {
  auto enable_brp = allocator_shim::EnableBrp(true);
-  size_t brp_extra_extras_size = 0;

  // Embedders's tests might benefit from MTE checks. However, this is costly
  // and shouldn't be used in benchmarks.
@ -180,15 +181,15 @@ PA_ALWAYS_INLINE void ConfigurePartitionsForTesting() {
  size_t scheduler_loop_quarantine_capacity_in_bytes = 0;
  auto zapping_by_free_flags = ZappingByFreeFlags(false);
  auto eventually_zero_freed_memory = EventuallyZeroFreedMemory(false);
-  auto fewer_memory_regions = FewerMemoryRegions(false);
+  auto use_pool_offset_freelists = UsePoolOffsetFreelists(true);
  auto use_small_single_slot_spans = UseSmallSingleSlotSpans(true);

-  ConfigurePartitions(enable_brp, brp_extra_extras_size, enable_memory_tagging,
+  ConfigurePartitions(enable_brp, enable_memory_tagging,
                      memory_tagging_reporting_mode, distribution,
                      scheduler_loop_quarantine,
                      scheduler_loop_quarantine_capacity_in_bytes,
                      zapping_by_free_flags, eventually_zero_freed_memory,
-                      fewer_memory_regions, use_small_single_slot_spans);
+                      use_pool_offset_freelists, use_small_single_slot_spans);
 }
 #endif  // PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)

--- a/src/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim_default_dispatch_to_winheap.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim_default_dispatch_to_winheap.cc
@ -2,10 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

+#include "partition_alloc/shim/allocator_shim.h"
+
 #include <ostream>

 #include "partition_alloc/partition_alloc_check.h"
-#include "partition_alloc/shim/allocator_shim.h"
 #include "partition_alloc/shim/winheap_stubs_win.h"

 namespace {
--- a/src/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim_override_ucrt_symbols_win.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim_override_ucrt_symbols_win.h
@ -276,7 +276,7 @@ errno_t _wdupenv_s(wchar_t** buffer,
 }
 #endif

-#if PA_BUILDFLAG(IS_DEBUG)
+#if !defined(NDEBUG)
 typedef void (*_CRT_DUMP_CLIENT)(void*, size_t);

 int _crtDbgFlag = 0;
@ -451,9 +451,9 @@ errno_t _wdupenv_s_dbg(wchar_t** buffer,
 }
 #endif  // defined(COMPONENT_BUILD)

-#endif  // PA_BUILDFLAG(IS_DEBUG)
+#endif  // !defined(NDEBUG)

-}       // extern "C"
+}  // extern "C"
 #endif  // PA_BUILDFLAG(USE_ALLOCATOR_SHIM)

 #endif  // PARTITION_ALLOC_SHIM_ALLOCATOR_SHIM_OVERRIDE_UCRT_SYMBOLS_WIN_H_
--- a/src/base/allocator/partition_allocator/src/partition_alloc/spinning_mutex.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/spinning_mutex.cc
@ -142,33 +142,8 @@ void SpinningMutex::LockSlow() {

 #elif PA_BUILDFLAG(IS_APPLE)

-// TODO(verwaest): We should use the constants from the header, but they aren't
-// exposed until macOS 15. See their definition here:
-// https://github.com/apple-oss-distributions/libplatform/blob/4f6349dfea579c35b8fa838d785644e441d14e0e/private/os/lock_private.h#L265
-//
-// The first flag prevents the runtime from creating more threads in response to
-// contention. The second will spin in the kernel if the lock owner is currently
-// running.
-#define OS_UNFAIR_LOCK_DATA_SYNCHRONIZATION 0x00010000
-#define OS_UNFAIR_LOCK_ADAPTIVE_SPIN 0x00040000
-
-typedef uint32_t os_unfair_lock_options_t;
-
-extern "C" {
-void __attribute__((weak))
-os_unfair_lock_lock_with_options(os_unfair_lock* lock,
-                                 os_unfair_lock_options_t);
-}
-
 void SpinningMutex::LockSlow() {
-  if (os_unfair_lock_lock_with_options) {
-    const os_unfair_lock_options_t options =
-        static_cast<os_unfair_lock_options_t>(
-            OS_UNFAIR_LOCK_DATA_SYNCHRONIZATION | OS_UNFAIR_LOCK_ADAPTIVE_SPIN);
-    os_unfair_lock_lock_with_options(&unfair_lock_, options);
-  } else {
-    os_unfair_lock_lock(&unfair_lock_);
-  }
+  return os_unfair_lock_lock(&unfair_lock_);
 }

 #elif PA_BUILDFLAG(IS_POSIX)
--- a/src/base/allocator/partition_allocator/src/partition_alloc/third_party/apple_apsl/README.chromium
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/third_party/apple_apsl/README.chromium
@ -4,7 +4,7 @@ Version: 409.40.6
 Revision: 387a5a03c017801ecdfe9cbe7f8d69a9b427df68
 Security Critical: yes
 Shipped: yes
-License: APSL-2.0
+License: Apple Public Source License 2.0
 License File: LICENSE

 Local Modifications:
--- a/src/base/allocator/partition_allocator/src/partition_alloc/thread_cache.cc
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/thread_cache.cc
@ -377,11 +377,7 @@ void ThreadCache::SwapForTesting(PartitionRoot* root) {
 // static
 void ThreadCache::RemoveTombstoneForTesting() {
  PA_CHECK(IsTombstone(Get()));
-#if PA_CONFIG(THREAD_CACHE_FAST_TLS)
-  internal::g_thread_cache = nullptr;
-#else
  internal::PartitionTlsSet(internal::g_thread_cache_key, nullptr);
-#endif
 }

 // static
--- a/src/base/allocator/partition_allocator/src/partition_alloc/thread_isolation/pkey.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/thread_isolation/pkey.h
@ -12,6 +12,7 @@
 #include <cstddef>
 #include <cstdint>

+#include "partition_alloc/buildflags.h"
 #include "partition_alloc/partition_alloc_base/component_export.h"
 #include "partition_alloc/thread_isolation/alignment.h"

--- a/src/base/allocator/partition_allocator/src/partition_alloc/thread_isolation/thread_isolation.h
+++ b/src/base/allocator/partition_allocator/src/partition_alloc/thread_isolation/thread_isolation.h
@ -12,6 +12,7 @@
 #include <cstddef>
 #include <cstdint>

+#include "partition_alloc/buildflags.h"
 #include "partition_alloc/partition_alloc_base/component_export.h"

 #if PA_BUILDFLAG(ENABLE_PKEYS)
--- a/src/base/android/android_info.cc
+++ b/src/base/android/android_info.cc
@ -1,196 +0,0 @@
-// Copyright 2025 The Chromium Authors
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "base/android/android_info.h"
-
-#include <cstring>
-#include <mutex>
-#include <string>
-#include <variant>
-
-#include "base/android/jni_android.h"
-#include "base/android/jni_array.h"
-#include "base/android/jni_string.h"
-#include "base/android/scoped_java_ref.h"
-#include "base/check.h"
-#include "base/strings/string_number_conversions.h"
-
-// Must come after all headers that specialize FromJniType() / ToJniType().
-#include "base/android_info_jni/AndroidInfo_jni.h"
-
-namespace base::android::android_info {
-
-namespace {
-
-struct AndroidInfo {
-  // Const char* is used instead of std::strings because these values must be
-  // available even if the process is in a crash state. Sadly
-  // std::string.c_str() doesn't guarantee that memory won't be allocated when
-  // it is called.
-  const char* device;
-
-  const char* manufacturer;
-
-  const char* model;
-
-  const char* brand;
-
-  const char* android_build_id;
-
-  const char* build_type;
-
-  const char* board;
-
-  const char* android_build_fp;
-
-  int sdk_int;
-
-  bool is_debug_android;
-
-  const char* version_incremental;
-
-  const char* hardware;
-
-  bool is_at_least_u;
-
-  const char* codename;
-
-  // Available only on android S+. For S-, this method returns empty string.
-  const char* soc_manufacturer;
-
-  bool is_at_least_t;
-
-  const char* abi_name;
-};
-
-std::optional<AndroidInfo> holder;
-
-const AndroidInfo& get_android_info() {
-  [[maybe_unused]] static auto once = [] {
-    Java_AndroidInfo_nativeReadyForFields(AttachCurrentThread());
-    return std::monostate();
-  }();
-  // holder should be initialized as the java is supposed to call the native
-  // method FillFields which will initialize the fields within the holder.
-  DCHECK(holder.has_value());
-  return *holder;
-}
-
-}  // namespace
-
-static void JNI_AndroidInfo_FillFields(
-    JNIEnv* env,
-    const jni_zero::JavaParamRef<jstring>& brand,
-    const jni_zero::JavaParamRef<jstring>& device,
-    const jni_zero::JavaParamRef<jstring>& buildId,
-    const jni_zero::JavaParamRef<jstring>& manufacturer,
-    const jni_zero::JavaParamRef<jstring>& model,
-    const jni_zero::JavaParamRef<jstring>& type,
-    const jni_zero::JavaParamRef<jstring>& board,
-    const jni_zero::JavaParamRef<jstring>& androidBuildFingerprint,
-    const jni_zero::JavaParamRef<jstring>& versionIncremental,
-    const jni_zero::JavaParamRef<jstring>& hardware,
-    const jni_zero::JavaParamRef<jstring>& codeName,
-    const jni_zero::JavaParamRef<jstring>& socManufacturer,
-    const jni_zero::JavaParamRef<jstring>& supportedAbis,
-    jint sdkInt,
-    jboolean isDebugAndroid,
-    jboolean isAtleastU,
-    jboolean isAtleastT) {
-  DCHECK(!holder.has_value());
-  auto java_string_to_const_char =
-      [](const jni_zero::JavaParamRef<jstring>& str) {
-        return strdup(ConvertJavaStringToUTF8(str).c_str());
-      };
-  holder = AndroidInfo{
-      .device = java_string_to_const_char(device),
-      .manufacturer = java_string_to_const_char(manufacturer),
-      .model = java_string_to_const_char(model),
-      .brand = java_string_to_const_char(brand),
-      .android_build_id = java_string_to_const_char(buildId),
-      .build_type = java_string_to_const_char(type),
-      .board = java_string_to_const_char(board),
-      .android_build_fp = java_string_to_const_char(androidBuildFingerprint),
-      .sdk_int = sdkInt,
-      .is_debug_android = static_cast<bool>(isDebugAndroid),
-      .version_incremental = java_string_to_const_char(versionIncremental),
-      .hardware = java_string_to_const_char(hardware),
-      .is_at_least_u = static_cast<bool>(isAtleastU),
-      .codename = java_string_to_const_char(codeName),
-      .soc_manufacturer = java_string_to_const_char(socManufacturer),
-      .is_at_least_t = static_cast<bool>(isAtleastT),
-      .abi_name = java_string_to_const_char(supportedAbis),
-  };
-}
-
-const char* device() {
-  return get_android_info().device;
-}
-
-const char* manufacturer() {
-  return get_android_info().manufacturer;
-}
-
-const char* model() {
-  return get_android_info().model;
-}
-
-const char* brand() {
-  return get_android_info().brand;
-}
-
-const char* android_build_id() {
-  return get_android_info().android_build_id;
-}
-
-const char* build_type() {
-  return get_android_info().build_type;
-}
-
-const char* board() {
-  return get_android_info().board;
-}
-
-const char* android_build_fp() {
-  return get_android_info().android_build_fp;
-}
-
-int sdk_int() {
-  return get_android_info().sdk_int;
-}
-
-bool is_debug_android() {
-  return get_android_info().is_debug_android;
-}
-
-const char* version_incremental() {
-  return get_android_info().version_incremental;
-}
-
-const char* hardware() {
-  return get_android_info().hardware;
-}
-
-bool is_at_least_u() {
-  return get_android_info().is_at_least_u;
-}
-
-const char* codename() {
-  return get_android_info().codename;
-}
-
-// Available only on android S+. For S-, this method returns empty string.
-const char* soc_manufacturer() {
-  return get_android_info().soc_manufacturer;
-}
-
-bool is_at_least_t() {
-  return get_android_info().is_at_least_t;
-}
-
-const char* abi_name() {
-  return get_android_info().abi_name;
-}
-
-}  // namespace base::android::android_info
--- a/src/base/android/android_info.h
+++ b/src/base/android/android_info.h
@ -1,74 +0,0 @@
-// Copyright 2025 The Chromium Authors
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef BASE_ANDROID_ANDROID_INFO_H_
-#define BASE_ANDROID_ANDROID_INFO_H_
-
-#include "base/base_export.h"
-
-namespace base::android::android_info {
-
-// This enumeration maps to the values returned by AndroidInfo::sdk_int(),
-// indicating the Android release associated with a given SDK version.
-enum SdkVersion {
-  SDK_VERSION_JELLY_BEAN = 16,
-  SDK_VERSION_JELLY_BEAN_MR1 = 17,
-  SDK_VERSION_JELLY_BEAN_MR2 = 18,
-  SDK_VERSION_KITKAT = 19,
-  SDK_VERSION_KITKAT_WEAR = 20,
-  SDK_VERSION_LOLLIPOP = 21,
-  SDK_VERSION_LOLLIPOP_MR1 = 22,
-  SDK_VERSION_MARSHMALLOW = 23,
-  SDK_VERSION_NOUGAT = 24,
-  SDK_VERSION_NOUGAT_MR1 = 25,
-  SDK_VERSION_OREO = 26,
-  SDK_VERSION_O_MR1 = 27,
-  SDK_VERSION_P = 28,
-  SDK_VERSION_Q = 29,
-  SDK_VERSION_R = 30,
-  SDK_VERSION_S = 31,
-  SDK_VERSION_Sv2 = 32,
-  SDK_VERSION_T = 33,
-  SDK_VERSION_U = 34,
-  SDK_VERSION_V = 35,
-};
-
-const char* device();
-
-const char* manufacturer();
-
-const char* model();
-
-BASE_EXPORT const char* brand();
-
-const char* android_build_id();
-
-const char* build_type();
-
-const char* board();
-
-const char* android_build_fp();
-
-BASE_EXPORT int sdk_int();
-
-bool is_debug_android();
-
-const char* version_incremental();
-
-BASE_EXPORT const char* hardware();
-
-bool is_at_least_u();
-
-const char* codename();
-
-// Available only on android S+. For S-, this method returns empty string.
-const char* soc_manufacturer();
-
-bool is_at_least_t();
-
-const char* abi_name();
-
-}  // namespace base::android::android_info
-
-#endif  // BASE_ANDROID_ANDROID_INFO_H_
--- a/src/base/android/apk_assets.cc
+++ b/src/base/android/apk_assets.cc
@ -2,10 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

-#include "base/android/apk_assets.h"
-
 #include <jni.h>

+#include "base/android/apk_assets.h"
+
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/android/scoped_java_ref.h"
@ -26,7 +26,8 @@ int OpenApkAsset(const std::string& file_path,
  // resources :(
  JNIEnv* env = base::android::AttachCurrentThread();
  ScopedJavaLocalRef<jlongArray> jarr =
-      Java_ApkAssets_open(env, file_path, split_name);
+      Java_ApkAssets_open(env, ConvertUTF8ToJavaString(env, file_path),
+                          ConvertUTF8ToJavaString(env, split_name));
  std::vector<jlong> results;
  base::android::JavaLongArrayToLongVector(env, jarr, &results);
  CHECK_EQ(3U, results.size());
@ -47,9 +48,8 @@ bool RegisterApkAssetWithFileDescriptorStore(const std::string& key,
  base::MemoryMappedFile::Region region =
      base::MemoryMappedFile::Region::kWholeFile;
  int asset_fd = OpenApkAsset(file_path.value(), &region);
-  if (asset_fd == -1) {
+  if (asset_fd == -1)
    return false;
-  }
  base::FileDescriptorStore::GetInstance().Set(key, base::ScopedFD(asset_fd),
                                               region);
  return true;
@ -57,11 +57,13 @@ bool RegisterApkAssetWithFileDescriptorStore(const std::string& key,

 void DumpLastOpenApkAssetFailure() {
  JNIEnv* env = base::android::AttachCurrentThread();
-  std::string error = Java_ApkAssets_takeLastErrorString(env);
-  if (error.empty()) {
+  base::android::ScopedJavaLocalRef<jstring> error =
+      Java_ApkAssets_takeLastErrorString(env);
+  if (!error) {
    return;
  }
-  SCOPED_CRASH_KEY_STRING256("base", "OpenApkAssetError", error);
+  SCOPED_CRASH_KEY_STRING256("base", "OpenApkAssetError",
+                             ConvertJavaStringToUTF8(env, error));
  base::debug::DumpWithoutCrashing();
 }

--- a/src/base/android/apk_assets.h
+++ b/src/base/android/apk_assets.h
@ -26,8 +26,9 @@ namespace android {
 BASE_EXPORT int OpenApkAsset(const std::string& file_path,
                             const std::string& split_name,
                             base::MemoryMappedFile::Region* region);
-BASE_EXPORT int OpenApkAsset(const std::string& file_path,
-                             base::MemoryMappedFile::Region* region);
+BASE_EXPORT int OpenApkAsset(
+    const std::string& file_path,
+    base::MemoryMappedFile::Region* region);

 // Registers an uncompressed asset from within the apk in the
 // FileDescriptorStore.
--- a/src/base/android/apk_info.cc
+++ b/src/base/android/apk_info.cc
@ -1,131 +0,0 @@
-// Copyright 2025 The Chromium Authors
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "base/android/apk_info.h"
-
-#include <string>
-#include <variant>
-
-#include "base/android/jni_android.h"
-#include "base/android/jni_array.h"
-#include "base/android/jni_string.h"
-#include "base/android/scoped_java_ref.h"
-#include "base/strings/string_number_conversions.h"
-
-// Must come after all headers that specialize FromJniType() / ToJniType().
-#include "base/build_info_jni/ApkInfo_jni.h"
-
-namespace base::android::apk_info {
-
-namespace {
-
-struct ApkInfo {
-  // Const char* is used instead of std::strings because these values must be
-  // available even if the process is in a crash state. Sadly
-  // std::string.c_str() doesn't guarantee that memory won't be allocated when
-  // it is called.
-  const char* host_package_name;
-  const char* host_version_code;
-  const char* host_package_label;
-  const char* package_version_code;
-  const char* package_version_name;
-  const char* package_name;
-  const char* resources_version;
-  const char* installer_package_name;
-  bool is_debug_app;
-  bool targets_at_least_u;
-  int target_sdk_version;
-};
-
-std::optional<ApkInfo> holder;
-
-ApkInfo& get_apk_info() {
-  [[maybe_unused]] static auto once = [] {
-    Java_ApkInfo_nativeReadyForFields(AttachCurrentThread());
-    return std::monostate();
-  }();
-  // holder should be initialized as the java is supposed to call the native
-  // method FillFields which will initialize the fields within the holder.
-  DCHECK(holder.has_value());
-  return *holder;
-}
-
-}  // namespace
-
-static void JNI_ApkInfo_FillFields(
-    JNIEnv* env,
-    const jni_zero::JavaParamRef<jstring>& hostPackageName,
-    const jni_zero::JavaParamRef<jstring>& hostVersionCode,
-    const jni_zero::JavaParamRef<jstring>& hostPackageLabel,
-    const jni_zero::JavaParamRef<jstring>& packageVersionCode,
-    const jni_zero::JavaParamRef<jstring>& packageVersionName,
-    const jni_zero::JavaParamRef<jstring>& packageName,
-    const jni_zero::JavaParamRef<jstring>& resourcesVersion,
-    const jni_zero::JavaParamRef<jstring>& installerPackageName,
-    jboolean isDebugApp,
-    jboolean targetsAtleastU,
-    jint targetSdkVersion) {
-  DCHECK(!holder.has_value());
-  auto java_string_to_const_char =
-      [](const jni_zero::JavaParamRef<jstring>& str) {
-        return strdup(ConvertJavaStringToUTF8(str).c_str());
-      };
-  holder = ApkInfo{
-      .host_package_name = java_string_to_const_char(hostPackageName),
-      .host_version_code = java_string_to_const_char(hostVersionCode),
-      .host_package_label = java_string_to_const_char(hostPackageLabel),
-      .package_version_code = java_string_to_const_char(packageVersionCode),
-      .package_version_name = java_string_to_const_char(packageVersionName),
-      .package_name = java_string_to_const_char(packageName),
-      .resources_version = java_string_to_const_char(resourcesVersion),
-      .installer_package_name = java_string_to_const_char(installerPackageName),
-      .is_debug_app = static_cast<bool>(isDebugApp),
-      .targets_at_least_u = static_cast<bool>(targetsAtleastU),
-      .target_sdk_version = targetSdkVersion};
-}
-
-const char* host_package_name() {
-  return get_apk_info().host_package_name;
-}
-
-const char* host_version_code() {
-  return get_apk_info().host_version_code;
-}
-
-const char* host_package_label() {
-  return get_apk_info().host_package_label;
-}
-
-const char* package_version_code() {
-  return get_apk_info().package_version_code;
-}
-
-const char* package_version_name() {
-  return get_apk_info().package_version_name;
-}
-
-const char* package_name() {
-  return get_apk_info().package_name;
-}
-
-const char* resources_version() {
-  return get_apk_info().resources_version;
-}
-
-const char* installer_package_name() {
-  return get_apk_info().installer_package_name;
-}
-
-bool is_debug_app() {
-  return get_apk_info().is_debug_app;
-}
-
-int target_sdk_version() {
-  return get_apk_info().target_sdk_version;
-}
-
-bool targets_at_least_u() {
-  return get_apk_info().targets_at_least_u;
-}
-}  // namespace base::android::apk_info
--- a/src/base/android/apk_info.h
+++ b/src/base/android/apk_info.h
@ -1,43 +0,0 @@
-// Copyright 2025 The Chromium Authors
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef BASE_ANDROID_APK_INFO_H_
-#define BASE_ANDROID_APK_INFO_H_
-
-namespace base::android::apk_info {
-// The package name of the host app which has loaded WebView, retrieved from
-// the application context. In the context of the SDK Runtime, the package
-// name of the app that owns this particular instance of the SDK Runtime will
-// also be included. e.g.
-// com.google.android.sdksandbox:com:com.example.myappwithads
-const char* host_package_name();
-
-// The application name (e.g. "Chrome"). For WebView, this is name of the
-// embedding app. In the context of the SDK Runtime, this is the name of the
-// app that owns this particular instance of the SDK Runtime.
-const char* host_version_code();
-
-// By default: same as versionCode. For WebView: versionCode of the embedding
-// app. In the context of the SDK Runtime, this is the versionCode of the app
-// that owns this particular instance of the SDK Runtime.
-const char* host_package_label();
-
-const char* package_version_code();
-
-const char* package_version_name();
-
-const char* package_name();
-
-const char* resources_version();
-
-const char* installer_package_name();
-
-bool is_debug_app();
-
-int target_sdk_version();
-
-bool targets_at_least_u();
-
-}  // namespace base::android::apk_info
-#endif  // BASE_ANDROID_APK_INFO_H_
--- a/src/base/android/application_status_listener.cc
+++ b/src/base/android/application_status_listener.cc
@ -66,9 +66,8 @@ class ApplicationStatusListenerImpl : public ApplicationStatusListener {
  }

  void Notify(ApplicationState state) override {
-    if (callback_) {
+    if (callback_)
      callback_.Run(state);
-    }
  }

 private:
@ -114,8 +113,9 @@ ApplicationState ApplicationStatusListener::GetState() {
      Java_ApplicationStatus_getStateForApplication(AttachCurrentThread()));
 }

-static void JNI_ApplicationStatus_OnApplicationStateChange(JNIEnv* env,
-                                                           jint new_state) {
+static void JNI_ApplicationStatus_OnApplicationStateChange(
+    JNIEnv* env,
+    jint new_state) {
  ApplicationState application_state = static_cast<ApplicationState>(new_state);
  ApplicationStatusListener::NotifyApplicationStateChange(application_state);
 }
--- a/src/base/android/application_status_listener.h
+++ b/src/base/android/application_status_listener.h
@ -6,7 +6,6 @@
 #define BASE_ANDROID_APPLICATION_STATUS_LISTENER_H_

 #include <jni.h>
-
 #include <memory>

 #include "base/android/jni_android.h"
--- a/src/base/android/base_feature_map.cc
+++ b/src/base/android/base_feature_map.cc
@ -22,8 +22,8 @@ const base::Feature* const kFeaturesExposedToJava[] = {

 // static
 base::android::FeatureMap* GetFeatureMap() {
-  static base::NoDestructor<base::android::FeatureMap> kFeatureMap(
-      kFeaturesExposedToJava);
+  static base::NoDestructor<base::android::FeatureMap> kFeatureMap(std::vector(
+      std::begin(kFeaturesExposedToJava), std::end(kFeaturesExposedToJava)));
  return kFeatureMap.get();
 }

--- a/src/base/android/build_info.cc
+++ b/src/base/android/build_info.cc
@ -6,9 +6,6 @@

 #include <string>

-#include "base/android/android_info.h"
-#include "base/android/apk_info.h"
-#include "base/android/device_info.h"
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
@ -19,13 +16,35 @@
 #include "base/strings/string_number_conversions.h"

 // Must come after all headers that specialize FromJniType() / ToJniType().
-#include "base/build_info_jni/BuildInfo_jni.h"
+#include "base/base_jni/BuildInfo_jni.h"

 namespace base {
 namespace android {

+namespace {
+
+// We are leaking these strings.
+const char* StrDupParam(const std::vector<std::string>& params, size_t index) {
+  return strdup(params[index].c_str());
+}
+
+int GetIntParam(const std::vector<std::string>& params, size_t index) {
+  int ret = 0;
+  bool success = StringToInt(params[index], &ret);
+  DCHECK(success);
+  return ret;
+}
+
+}  // namespace
+
 struct BuildInfoSingletonTraits {
-  static BuildInfo* New() { return new BuildInfo(); }
+  static BuildInfo* New() {
+    JNIEnv* env = AttachCurrentThread();
+    ScopedJavaLocalRef<jobjectArray> params_objs = Java_BuildInfo_getAll(env);
+    std::vector<std::string> params;
+    AppendJavaStringArrayToStringVector(env, params_objs, &params);
+    return new BuildInfo(params);
+  }

  static void Delete(BuildInfo* x) {
    // We're leaking this type, see kRegisterAtExit.
@ -38,60 +57,62 @@ struct BuildInfoSingletonTraits {
 #endif
 };

-BuildInfo::BuildInfo()
-    : brand_(android_info::brand()),
-      device_(android_info::device()),
-      android_build_id_(android_info::android_build_id()),
-      manufacturer_(android_info::manufacturer()),
-      model_(android_info::model()),
-      sdk_int_(android_info::sdk_int()),
-      build_type_(android_info::build_type()),
-      board_(android_info::board()),
-      host_package_name_(apk_info::host_package_name()),
-      host_version_code_(apk_info::host_version_code()),
-      host_package_label_(apk_info::host_package_label()),
-      package_name_(apk_info::package_name()),
-      package_version_code_(apk_info::package_version_code()),
-      package_version_name_(apk_info::package_version_name()),
-      android_build_fp_(android_info::android_build_fp()),
-      installer_package_name_(apk_info::installer_package_name()),
-      abi_name_(android_info::abi_name()),
-      resources_version_(apk_info::resources_version()),
-      target_sdk_version_(apk_info::target_sdk_version()),
-      is_debug_android_(android_info::is_debug_android()),
-      is_tv_(device_info::is_tv()),
-      version_incremental_(android_info::version_incremental()),
-      hardware_(android_info::hardware()),
-      is_at_least_t_(android_info::is_at_least_t()),
-      is_automotive_(device_info::is_automotive()),
-      is_at_least_u_(android_info::is_at_least_u()),
-      targets_at_least_u_(apk_info::targets_at_least_u()),
-      codename_(android_info::codename()),
-      vulkan_deqp_level_(device_info::vulkan_deqp_level()),
-      is_foldable_(device_info::is_foldable()),
-      soc_manufacturer_(android_info::soc_manufacturer()),
-      is_debug_app_(apk_info::is_debug_app()),
-      is_desktop_(device_info::is_desktop()) {}
+BuildInfo::BuildInfo(const std::vector<std::string>& params)
+    : brand_(StrDupParam(params, 0)),
+      device_(StrDupParam(params, 1)),
+      android_build_id_(StrDupParam(params, 2)),
+      manufacturer_(StrDupParam(params, 3)),
+      model_(StrDupParam(params, 4)),
+      sdk_int_(GetIntParam(params, 5)),
+      build_type_(StrDupParam(params, 6)),
+      board_(StrDupParam(params, 7)),
+      host_package_name_(StrDupParam(params, 8)),
+      host_version_code_(StrDupParam(params, 9)),
+      host_package_label_(StrDupParam(params, 10)),
+      package_name_(StrDupParam(params, 11)),
+      package_version_code_(StrDupParam(params, 12)),
+      package_version_name_(StrDupParam(params, 13)),
+      android_build_fp_(StrDupParam(params, 14)),
+      gms_version_code_(StrDupParam(params, 15)),
+      installer_package_name_(StrDupParam(params, 16)),
+      abi_name_(StrDupParam(params, 17)),
+      custom_themes_(StrDupParam(params, 18)),
+      resources_version_(StrDupParam(params, 19)),
+      target_sdk_version_(GetIntParam(params, 20)),
+      is_debug_android_(GetIntParam(params, 21)),
+      is_tv_(GetIntParam(params, 22)),
+      version_incremental_(StrDupParam(params, 23)),
+      hardware_(StrDupParam(params, 24)),
+      is_at_least_t_(GetIntParam(params, 25)),
+      is_automotive_(GetIntParam(params, 26)),
+      is_at_least_u_(GetIntParam(params, 27)),
+      targets_at_least_u_(GetIntParam(params, 28)),
+      codename_(StrDupParam(params, 29)),
+      vulkan_deqp_level_(GetIntParam(params, 30)),
+      is_foldable_(GetIntParam(params, 31)),
+      soc_manufacturer_(StrDupParam(params, 32)),
+      is_debug_app_(GetIntParam(params, 33)),
+      is_desktop_(GetIntParam(params, 34)) {}

 BuildInfo::~BuildInfo() = default;

-const char* BuildInfo::gms_version_code() const {
-  return device_info::gms_version_code();
-}
-
 void BuildInfo::set_gms_version_code_for_test(
    const std::string& gms_version_code) {
-  device_info::set_gms_version_code_for_test(gms_version_code);
+  // This leaks the string, just like production code.
+  gms_version_code_ = strdup(gms_version_code.c_str());
+  Java_BuildInfo_setGmsVersionCodeForTest(AttachCurrentThread(),
+                                          gms_version_code);
 }

 std::string BuildInfo::host_signing_cert_sha256() {
  JNIEnv* env = AttachCurrentThread();
-  return Java_BuildInfo_lazyGetHostSigningCertSha256(env);
+  return base::android::ConvertJavaStringToUTF8(
+      env, Java_BuildInfo_lazyGetHostSigningCertSha256(env));
 }

 // static
 BuildInfo* BuildInfo::GetInstance() {
-  return Singleton<BuildInfo, BuildInfoSingletonTraits>::get();
+  return Singleton<BuildInfo, BuildInfoSingletonTraits >::get();
 }

 }  // namespace android
--- a/src/base/android/build_info.h
+++ b/src/base/android/build_info.h
@ -10,42 +10,36 @@
 #include <string>
 #include <vector>

-#include "base/android/android_info.h"
 #include "base/base_export.h"
 #include "base/memory/singleton.h"

 namespace base::android {

-// DEPRECATED: Please use android_info::SdkVersion.
-//
 // This enumeration maps to the values returned by BuildInfo::sdk_int(),
 // indicating the Android release associated with a given SDK version.
 enum SdkVersion {
-  SDK_VERSION_JELLY_BEAN = android_info::SDK_VERSION_JELLY_BEAN,
-  SDK_VERSION_JELLY_BEAN_MR1 = android_info::SDK_VERSION_JELLY_BEAN_MR1,
-  SDK_VERSION_JELLY_BEAN_MR2 = android_info::SDK_VERSION_JELLY_BEAN_MR2,
-  SDK_VERSION_KITKAT = android_info::SDK_VERSION_KITKAT,
-  SDK_VERSION_KITKAT_WEAR = android_info::SDK_VERSION_KITKAT_WEAR,
-  SDK_VERSION_LOLLIPOP = android_info::SDK_VERSION_LOLLIPOP,
-  SDK_VERSION_LOLLIPOP_MR1 = android_info::SDK_VERSION_LOLLIPOP_MR1,
-  SDK_VERSION_MARSHMALLOW = android_info::SDK_VERSION_MARSHMALLOW,
-  SDK_VERSION_NOUGAT = android_info::SDK_VERSION_NOUGAT,
-  SDK_VERSION_NOUGAT_MR1 = android_info::SDK_VERSION_NOUGAT_MR1,
-  SDK_VERSION_OREO = android_info::SDK_VERSION_OREO,
-  SDK_VERSION_O_MR1 = android_info::SDK_VERSION_O_MR1,
-  SDK_VERSION_P = android_info::SDK_VERSION_P,
-  SDK_VERSION_Q = android_info::SDK_VERSION_Q,
-  SDK_VERSION_R = android_info::SDK_VERSION_R,
-  SDK_VERSION_S = android_info::SDK_VERSION_S,
-  SDK_VERSION_Sv2 = android_info::SDK_VERSION_Sv2,
-  SDK_VERSION_T = android_info::SDK_VERSION_T,
-  SDK_VERSION_U = android_info::SDK_VERSION_U,
-  SDK_VERSION_V = android_info::SDK_VERSION_V,
+  SDK_VERSION_JELLY_BEAN = 16,
+  SDK_VERSION_JELLY_BEAN_MR1 = 17,
+  SDK_VERSION_JELLY_BEAN_MR2 = 18,
+  SDK_VERSION_KITKAT = 19,
+  SDK_VERSION_KITKAT_WEAR = 20,
+  SDK_VERSION_LOLLIPOP = 21,
+  SDK_VERSION_LOLLIPOP_MR1 = 22,
+  SDK_VERSION_MARSHMALLOW = 23,
+  SDK_VERSION_NOUGAT = 24,
+  SDK_VERSION_NOUGAT_MR1 = 25,
+  SDK_VERSION_OREO = 26,
+  SDK_VERSION_O_MR1 = 27,
+  SDK_VERSION_P = 28,
+  SDK_VERSION_Q = 29,
+  SDK_VERSION_R = 30,
+  SDK_VERSION_S = 31,
+  SDK_VERSION_Sv2 = 32,
+  SDK_VERSION_T = 33,
+  SDK_VERSION_U = 34,
+  SDK_VERSION_V = 35,
 };

-// DEPRECATED: Use AndroidInfo, DeviceInfo or ApkInfo instead.
-// These are more efficient because they only retrieve the data being queried.
-//
 // BuildInfo is a singleton class that stores android build and device
 // information. It will be called from Android specific code and gets used
 // primarily in crash reporting.
@ -66,19 +60,33 @@ class BASE_EXPORT BuildInfo {
  // available even if the process is in a crash state. Sadly
  // std::string.c_str() doesn't guarantee that memory won't be allocated when
  // it is called.
-  const char* device() const { return device_; }
+  const char* device() const {
+    return device_;
+  }

-  const char* manufacturer() const { return manufacturer_; }
+  const char* manufacturer() const {
+    return manufacturer_;
+  }

-  const char* model() const { return model_; }
+  const char* model() const {
+    return model_;
+  }

-  const char* brand() const { return brand_; }
+  const char* brand() const {
+    return brand_;
+  }

-  const char* android_build_id() const { return android_build_id_; }
+  const char* android_build_id() const {
+    return android_build_id_;
+  }

-  const char* android_build_fp() const { return android_build_fp_; }
+  const char* android_build_fp() const {
+    return android_build_fp_;
+  }

-  const char* gms_version_code() const;
+  const char* gms_version_code() const {
+    return gms_version_code_;
+  }

  void set_gms_version_code_for_test(const std::string& gms_version_code);

@ -103,15 +111,25 @@ class BASE_EXPORT BuildInfo {
  // This will default to an empty string if we were unable to retrieve it.
  std::string host_signing_cert_sha256();

-  const char* package_version_code() const { return package_version_code_; }
+  const char* package_version_code() const {
+    return package_version_code_;
+  }

-  const char* package_version_name() const { return package_version_name_; }
+  const char* package_version_name() const {
+    return package_version_name_;
+  }

-  const char* package_name() const { return package_name_; }
+  const char* package_name() const {
+    return package_name_;
+  }
+
+  const char* custom_themes() const { return custom_themes_; }

  const char* resources_version() const { return resources_version_; }

-  const char* build_type() const { return build_type_; }
+  const char* build_type() const {
+    return build_type_;
+  }

  const char* board() const { return board_; }

@ -119,7 +137,9 @@ class BASE_EXPORT BuildInfo {

  const char* abi_name() const { return abi_name_; }

-  int sdk_int() const { return sdk_int_; }
+  int sdk_int() const {
+    return sdk_int_;
+  }

  // Returns the targetSdkVersion of the currently running app. If called from a
  // library, this returns the embedding app's targetSdkVersion.
@ -162,7 +182,7 @@ class BASE_EXPORT BuildInfo {
 private:
  friend struct BuildInfoSingletonTraits;

-  explicit BuildInfo();
+  explicit BuildInfo(const std::vector<std::string>& params);

  // Const char* is used instead of std::strings because these values must be
  // available even if the process is in a crash state. Sadly
@ -183,8 +203,11 @@ class BASE_EXPORT BuildInfo {
  const char* const package_version_code_;
  const char* const package_version_name_;
  const char* const android_build_fp_;
+  // Can be overridden in tests.
+  const char* gms_version_code_ = nullptr;
  const char* const installer_package_name_;
  const char* const abi_name_;
+  const char* const custom_themes_;
  const char* const resources_version_;
  // Not needed by breakpad.
  const int target_sdk_version_;
--- a/src/base/android/build_info_stub.cc
+++ b/src/base/android/build_info_stub.cc
@ -22,7 +22,7 @@ namespace base {
 namespace android {

 struct BuildInfoSingletonTraits {
-  static BuildInfo* New() { return new BuildInfo(); }
+  static BuildInfo* New() { return new BuildInfo({}); }

  static void Delete(BuildInfo* x) {
    // We're leaking this type, see kRegisterAtExit.
@ -32,7 +32,7 @@ struct BuildInfoSingletonTraits {
  static const bool kRegisterAtExit = false;
 };

-BuildInfo::BuildInfo()
+BuildInfo::BuildInfo(const std::vector<std::string>& params)
    : brand_(""),
      device_(""),
      android_build_id_(""),
@ -48,8 +48,10 @@ BuildInfo::BuildInfo()
      package_version_code_(""),
      package_version_name_(""),
      android_build_fp_(""),
+      gms_version_code_(""),
      installer_package_name_(""),
      abi_name_(""),
+      custom_themes_(""),
      resources_version_(""),
      target_sdk_version_(0),
      is_debug_android_(false),
--- a/src/base/android/bundle_utils.cc
+++ b/src/base/android/bundle_utils.cc
@ -55,12 +55,19 @@ UNSAFE_BUFFER_USAGE void* ReadRelPtr(int32_t* relptr) {
 std::string BundleUtils::ResolveLibraryPath(const std::string& library_name,
                                            const std::string& split_name) {
  JNIEnv* env = AttachCurrentThread();
-  return Java_BundleUtils_getNativeLibraryPath(env, library_name, split_name);
+  ScopedJavaLocalRef<jstring> java_path = Java_BundleUtils_getNativeLibraryPath(
+      env, ConvertUTF8ToJavaString(env, library_name),
+      ConvertUTF8ToJavaString(env, split_name));
+  // TODO(crbug.com/40656179): Remove this tolerance.
+  if (!java_path) {
+    return std::string();
+  }
+  return ConvertJavaStringToUTF8(env, java_path);
 }

 // static
 bool BundleUtils::IsBundle() {
-  return Java_BundleUtils_isBundle(AttachCurrentThread());
+  return Java_BundleUtils_isBundleForNative(AttachCurrentThread());
 }

 // static
@ -107,7 +114,7 @@ void* BundleUtils::DlOpenModuleLibraryPartition(const std::string& library_name,
 #else
      // When targeting pre-N, such as for Cronet, android_dlopen_ext() might
      // not be available on the system.
-      NOTREACHED() << "android_dlopen_ext not available";
+      CHECK(0) << "android_dlopen_ext not available";
 #endif
    }
  }
--- a/src/base/android/callback_android.cc
+++ b/src/base/android/callback_android.cc
@ -10,9 +10,13 @@
 #include "base/android/scoped_java_ref.h"
 #include "base/time/time.h"
 #include "base/types/optional_ref.h"
+#include "build/robolectric_buildflags.h"

-// Must come after all headers that specialize FromJniType() / ToJniType().
+#if BUILDFLAG(IS_ROBOLECTRIC)
+#include "base/base_robolectric_jni/Callback_jni.h"  // nogncheck
+#else
 #include "base/callback_jni/Callback_jni.h"
+#endif

 namespace base {
 namespace android {
--- a/src/base/android/child_process_service.cc
+++ b/src/base/android/child_process_service.cc
@ -7,7 +7,6 @@
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/android/library_loader/library_loader_hooks.h"
-#include "base/android/pre_freeze_background_memory_trimmer.h"
 #include "base/debug/dump_without_crashing.h"
 #include "base/file_descriptor_store.h"
 #include "base/logging.h"
@ -83,9 +82,5 @@ NOINLINE void JNI_ChildProcessService_DumpProcessStack(JNIEnv* env) {
  base::debug::DumpWithoutCrashing();
 }

-void JNI_ChildProcessService_OnSelfFreeze(JNIEnv* env) {
-  PreFreezeBackgroundMemoryTrimmer::OnSelfFreeze();
-}
-
 }  // namespace android
 }  // namespace base
--- a/src/base/android/command_line_android.cc
+++ b/src/base/android/command_line_android.cc
@ -5,20 +5,24 @@
 #include "base/command_line.h"

 #include "base/android/jni_string.h"
+#include "build/robolectric_buildflags.h"

 // Must come after all headers that specialize FromJniType() / ToJniType().
+#if BUILDFLAG(IS_ROBOLECTRIC)
+#include "base/base_robolectric_jni/CommandLine_jni.h"  // nogncheck
+#else
 #include "base/command_line_jni/CommandLine_jni.h"
+#endif

-using base::CommandLine;
 using base::android::JavaParamRef;
 using base::android::ScopedJavaLocalRef;
+using base::CommandLine;

 namespace {

 void AppendToCommandLine(std::vector<std::string>& vec, bool includes_program) {
-  if (!includes_program) {
+  if (!includes_program)
    vec.insert(vec.begin(), std::string());
-  }
  CommandLine extra_command_line(vec);
  CommandLine::ForCurrentProcess()->AppendArguments(extra_command_line,
                                                    includes_program);
@ -36,8 +40,21 @@ static std::string JNI_CommandLine_GetSwitchValue(JNIEnv* env,
  return CommandLine::ForCurrentProcess()->GetSwitchValueNative(switch_string);
 }

-static CommandLine::SwitchMap JNI_CommandLine_GetSwitches(JNIEnv* env) {
-  return CommandLine::ForCurrentProcess()->GetSwitches();
+static std::vector<std::string> JNI_CommandLine_GetSwitchesFlattened(
+    JNIEnv* env) {
+  // JNI doesn't support returning Maps. Instead, express this map as a 1
+  // dimensional array: [ key1, value1, key2, value2, ... ]
+  std::vector<std::string> keys_and_values;
+  for (const auto& entry : CommandLine::ForCurrentProcess()->GetSwitches()) {
+    keys_and_values.push_back(entry.first);
+    keys_and_values.push_back(entry.second);
+  }
+  return keys_and_values;
+}
+
+static void JNI_CommandLine_AppendSwitch(JNIEnv* env,
+                                         std::string& switch_string) {
+  CommandLine::ForCurrentProcess()->AppendSwitch(switch_string);
 }

 static void JNI_CommandLine_AppendSwitchWithValue(JNIEnv* env,
--- a/src/base/android/content_uri_utils.cc
+++ b/src/base/android/content_uri_utils.cc
@ -22,6 +22,15 @@ using base::android::JavaRef;
 using base::android::ScopedJavaLocalRef;

 namespace base {
+namespace {
+std::string SafeConvertJavaStringToUTF8(JNIEnv* env,
+                                        const JavaRef<jstring>& str) {
+  if (str.is_null()) {
+    return std::string();
+  }
+  return base::android::ConvertJavaStringToUTF8(env, str);
+}
+}  // namespace

 namespace internal {

@ -105,30 +114,33 @@ bool IsDocumentUri(const FilePath& content_uri) {

 }  // namespace internal

-void JNI_ContentUriUtils_AddFileInfoToVector(JNIEnv* env,
-                                             jlong vector_pointer,
-                                             std::string& uri,
-                                             std::string& display_name,
-                                             jboolean is_directory,
-                                             jlong size,
-                                             jlong last_modified) {
+void JNI_ContentUriUtils_AddFileInfoToVector(
+    JNIEnv* env,
+    jlong vector_pointer,
+    const JavaParamRef<jstring>& uri,
+    const JavaParamRef<jstring>& display_name,
+    jboolean is_directory,
+    jlong size,
+    jlong last_modified) {
  auto* result =
      reinterpret_cast<std::vector<FileEnumerator::FileInfo>*>(vector_pointer);
-  result->emplace_back(FilePath(uri), FilePath(display_name), is_directory,
-                       size,
+  result->emplace_back(FilePath(SafeConvertJavaStringToUTF8(env, uri)),
+                       FilePath(SafeConvertJavaStringToUTF8(env, display_name)),
+                       is_directory, size,
                       Time::FromMillisecondsSinceUnixEpoch(last_modified));
 }

 std::string GetContentUriMimeType(const FilePath& content_uri) {
  JNIEnv* env = android::AttachCurrentThread();
-  return Java_ContentUriUtils_getMimeType(env, content_uri.value());
+  ScopedJavaLocalRef<jstring> j_mime =
+      Java_ContentUriUtils_getMimeType(env, content_uri.value());
+  return SafeConvertJavaStringToUTF8(env, j_mime);
 }

 bool MaybeGetFileDisplayName(const FilePath& content_uri,
                             std::u16string* file_display_name) {
-  if (!content_uri.IsContentUri()) {
+  if (!content_uri.IsContentUri())
    return false;
-  }

  DCHECK(file_display_name);

@ -136,9 +148,8 @@ bool MaybeGetFileDisplayName(const FilePath& content_uri,
  ScopedJavaLocalRef<jstring> j_display_name =
      Java_ContentUriUtils_maybeGetDisplayName(env, content_uri.value());

-  if (j_display_name.is_null()) {
+  if (j_display_name.is_null())
    return false;
-  }

  *file_display_name = android::ConvertJavaStringToUTF16(j_display_name);
  return true;
@ -148,9 +159,10 @@ FilePath ContentUriBuildDocumentUriUsingTree(
    const FilePath& tree_uri,
    const std::string& encoded_document_id) {
  JNIEnv* env = android::AttachCurrentThread();
-  std::string j_uri = Java_ContentUriUtils_buildDocumentUriUsingTree(
-      env, tree_uri.value(), encoded_document_id);
-  return FilePath(j_uri);
+  ScopedJavaLocalRef<jstring> j_uri =
+      Java_ContentUriUtils_buildDocumentUriUsingTree(env, tree_uri.value(),
+                                                     encoded_document_id);
+  return FilePath(SafeConvertJavaStringToUTF8(env, j_uri));
 }

 FilePath ContentUriGetChildDocumentOrQuery(const FilePath& parent,
@ -159,9 +171,10 @@ FilePath ContentUriGetChildDocumentOrQuery(const FilePath& parent,
                                           bool is_directory,
                                           bool create) {
  JNIEnv* env = android::AttachCurrentThread();
-  std::string j_uri = Java_ContentUriUtils_getChildDocumentOrQuery(
-      env, parent.value(), display_name, mime_type, is_directory, create);
-  return FilePath(j_uri);
+  ScopedJavaLocalRef<jstring> j_uri =
+      Java_ContentUriUtils_getChildDocumentOrQuery(
+          env, parent.value(), display_name, mime_type, is_directory, create);
+  return FilePath(SafeConvertJavaStringToUTF8(env, j_uri));
 }

 bool ContentUriIsCreateChildDocumentQuery(const FilePath& content_uri) {
@ -173,9 +186,9 @@ bool ContentUriIsCreateChildDocumentQuery(const FilePath& content_uri) {
 FilePath ContentUriGetDocumentFromQuery(const FilePath& content_uri,
                                        bool create) {
  JNIEnv* env = android::AttachCurrentThread();
-  std::string j_uri = Java_ContentUriUtils_getDocumentFromQuery(
+  ScopedJavaLocalRef<jstring> j_uri = Java_ContentUriUtils_getDocumentFromQuery(
      env, content_uri.value(), create);
-  return FilePath(j_uri);
+  return FilePath(SafeConvertJavaStringToUTF8(env, j_uri));
 }

 }  // namespace base
--- a/Show more
+++ b/Show more