Adding discardable memory dump provider.

content/child/child_discardable_shared_memory_manager.h

Index: content/child/child_discardable_shared_memory_manager.h
diff --git a/content/child/child_discardable_shared_memory_manager.h b/content/child/child_discardable_shared_memory_manager.h
index 881b59ec1dfe69a179af749bccb9e963faf4148c..02e0076c21875021a7471452862068befa83a57e 100644
--- a/content/child/child_discardable_shared_memory_manager.h
+++ b/content/child/child_discardable_shared_memory_manager.h
@@ -8,6 +8,7 @@
 #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"
@@ -18,7 +19,8 @@ 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;
@@ -34,6 +36,10 @@ class CONTENT_EXPORT ChildDiscardableSharedMemoryManager
   void UnlockSpan(DiscardableSharedMemoryHeap::Span* span);
   void ReleaseSpan(scoped_ptr<DiscardableSharedMemoryHeap::Span> span);
 
+  // base::trace_event::MemoryDumpProvider implementation:

[reveman, 2015/04/23 17:32:30]

nit: "Overridden from base::trace_event::MemoryDumpProvider" to be consistent
with the comment above

[ssid, 2015/04/24 11:23:04]

Done.

+  bool DumpInto(base::trace_event::ProcessMemoryDump* pmd) override;
+  const char* GetFriendlyName() const override;

[reveman, 2015/04/23 17:32:30]

nit: please move this functions just below the functions that implement
base::DiscardableMemoryAllocator and have the order in the .cc file match. The
idea is to have functions that implement different interfaces above other
functions.

[ssid, 2015/04/24 11:23:04]

Done.

+
  private:
   scoped_ptr<base::DiscardableSharedMemory>
   AllocateLockedDiscardableSharedMemory(size_t size,