base/allocator: Enable PAMemoryReclaimer for PA-Everywhere

Runs PartitionAllocMemoryReclaimer for the PartitionRoot used by
ShimMalloc, etc. (partition alloc as malloc).

Change-Id: I636b7b2ca4fdda7de7b3a178e6193dea7c0605cd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2532476Reviewed-by: Will Harris <wfh@chromium.org>
Reviewed-by: Ken Rockot <rockot@google.com>
Reviewed-by: Benoit L <lizeb@chromium.org>
Reviewed-by: Bartek Nowierski <bartekn@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#829063}

base/allocator/allocator_shim.h

@@ -151,6 +151,10 @@ BASE_EXPORT void RemoveAllocatorDispatchForTesting(AllocatorDispatch* dispatch);
 BASE_EXPORT void InitializeAllocatorShim();
 #endif  // defined(OS_APPLE)
 
+#if BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
+BASE_EXPORT void EnablePartitionAllocMemoryReclaimer();
+#endif
+
 #if BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
 BASE_EXPORT void EnablePCScanIfNeeded();
 #endif

base/allocator/allocator_shim_default_dispatch_to_partition_alloc.cc

@@ -5,6 +5,7 @@
 #include "base/allocator/allocator_shim_default_dispatch_to_partition_alloc.h"
 
 #include "base/allocator/allocator_shim_internals.h"
+#include "base/allocator/partition_allocator/memory_reclaimer.h"
 #include "base/allocator/partition_allocator/partition_alloc.h"
 #include "base/allocator/partition_allocator/partition_alloc_constants.h"
 #include "base/allocator/partition_allocator/partition_alloc_features.h"
@@ -225,6 +226,17 @@ ThreadSafePartitionRoot* PartitionAllocMalloc::AlignedAllocator() {
 namespace base {
 namespace allocator {
 
+void EnablePartitionAllocMemoryReclaimer() {
+  // Allocator() and AlignedAllocator() do not register their PartitionRoots to
+  // the memory reclaimer because the memory reclaimer allocates memory.  Thus,
+  // the registration to the memory reclaimer should be done sometime later.
+  // This function will be called sometime appropriate after PartitionRoots are
+  // initialized.
+  PartitionAllocMemoryReclaimer::Instance()->RegisterPartition(Allocator());
+  PartitionAllocMemoryReclaimer::Instance()->RegisterPartition(
+      AlignedAllocator());
+}
+
 void EnablePCScanIfNeeded() {
   if (!features::IsPartitionAllocPCScanEnabled())
     return;

content/app/content_main_runner_impl.cc

@@ -695,6 +695,9 @@ int ContentMainRunnerImpl::Initialize(const ContentMainParams& params) {
   // overriding logic is working correctly. If not causes a hard crash, as its
   // unexpected absence has security implications.
   CHECK(base::allocator::IsAllocatorInitialized());
+#if BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
+  base::allocator::EnablePartitionAllocMemoryReclaimer();
+#endif
 
 #if defined(OS_POSIX) || defined(OS_FUCHSIA)
   if (!process_type.empty()) {