Adding discardable memory dump provider.

content/child/child_discardable_shared_memory_manager.h

 // Copyright 2014 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 CONTENT_CHILD_CHILD_DISCARDABLE_SHARED_MEMORY_MANAGER_H_
 #define CONTENT_CHILD_CHILD_DISCARDABLE_SHARED_MEMORY_MANAGER_H_
 
 #include "base/memory/discardable_memory_allocator.h"
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
+#include "base/trace_event/memory_dump_provider.h"
 #include "content/child/thread_safe_sender.h"
 #include "content/common/content_export.h"
 #include "content/common/discardable_shared_memory_heap.h"
 #include "content/common/host_discardable_shared_memory_manager.h"
 
 namespace content {
 
 // Implementation of DiscardableMemoryAllocator that allocates
 // discardable memory segments through the browser process.
 class CONTENT_EXPORT ChildDiscardableSharedMemoryManager
-    : public base::DiscardableMemoryAllocator {
+    : public base::DiscardableMemoryAllocator,
+      public base::trace_event::MemoryDumpProvider {
  public:
   explicit ChildDiscardableSharedMemoryManager(ThreadSafeSender* sender);
   ~ChildDiscardableSharedMemoryManager() override;
 
   // Overridden from base::DiscardableMemoryAllocator:
   scoped_ptr<base::DiscardableMemory> AllocateLockedDiscardableMemory(
       size_t size) override;
 
+  // Overridden from base::trace_event::MemoryDumpProvider:
+  bool OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd) override;
+
   // Release memory and associated resources that have been purged.
   void ReleaseFreeMemory();
 
   bool LockSpan(DiscardableSharedMemoryHeap::Span* span);
   void UnlockSpan(DiscardableSharedMemoryHeap::Span* span);
   void ReleaseSpan(scoped_ptr<DiscardableSharedMemoryHeap::Span> span);
 
  private:
   scoped_ptr<base::DiscardableSharedMemory>
   AllocateLockedDiscardableSharedMemory(size_t size,
                                         DiscardableSharedMemoryId id);
   void MemoryUsageChanged(size_t new_bytes_allocated,
                           size_t new_bytes_free) const;
 
   mutable base::Lock lock_;
   DiscardableSharedMemoryHeap heap_;
   scoped_refptr<ThreadSafeSender> sender_;
 
   DISALLOW_COPY_AND_ASSIGN(ChildDiscardableSharedMemoryManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_CHILD_DISCARDABLE_SHARED_MEMORY_MANAGER_H_