Enable sharding of AllocationRegister on desktop.

base/trace_event/malloc_dump_provider.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_TRACE_EVENT_MALLOC_DUMP_PROVIDER_H_
 #define BASE_TRACE_EVENT_MALLOC_DUMP_PROVIDER_H_
 
 #include <istream>
 #include <memory>
 
 #include "base/macros.h"
 #include "base/memory/singleton.h"
-#include "base/synchronization/lock.h"
 #include "base/threading/platform_thread.h"
 #include "base/trace_event/memory_dump_provider.h"
 #include "build/build_config.h"
 
 #if defined(OS_LINUX) || defined(OS_ANDROID) || defined(OS_WIN) || \
     (defined(OS_MACOSX) && !defined(OS_IOS))
 #define MALLOC_MEMORY_TRACING_SUPPORTED
 #endif
 
 namespace base {
 namespace trace_event {
 
-class AllocationRegister;
+class ShardedAllocationRegister;
 
 // Dump provider which collects process-wide memory stats.
 class BASE_EXPORT MallocDumpProvider : public MemoryDumpProvider {
  public:
   // Name of the allocated_objects dump. Use this to declare suballocator dumps
   // from other dump providers.
   static const char kAllocatedObjects[];
 
   static MallocDumpProvider* GetInstance();
 
   // MemoryDumpProvider implementation.
   bool OnMemoryDump(const MemoryDumpArgs& args,
                     ProcessMemoryDump* pmd) override;
 
   void OnHeapProfilingEnabled(bool enabled) override;
 
   // For heap profiling.
   void InsertAllocation(void* address, size_t size);
   void RemoveAllocation(void* address);
 
  private:
   friend struct DefaultSingletonTraits<MallocDumpProvider>;
 
   MallocDumpProvider();
   ~MallocDumpProvider() override;
 
   // For heap profiling.
-  bool heap_profiler_enabled_;
-  std::unique_ptr<AllocationRegister> allocation_register_;
-  Lock allocation_register_lock_;
+  std::unique_ptr<ShardedAllocationRegister> allocation_register_;

[Primiano Tucci (use gerrit), 2017/05/22 16:37:50]

there is no need for a unique_ptr anymore here now, this could just be a field,
right?

[erikchen, 2017/05/22 17:10:42]

Done.

 
   // When in OnMemoryDump(), this contains the current thread ID.
   // This is to prevent re-entrancy in the heap profiler when the heap dump
   // generation is malloc/new-ing for its own bookeeping data structures.
   PlatformThreadId tid_dumping_heap_;
 
   DISALLOW_COPY_AND_ASSIGN(MallocDumpProvider);
 };
 
 }  // namespace trace_event
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_MALLOC_DUMP_PROVIDER_H_