Add support to create memory allocator dump in base::DiscardableMemory

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 6986955f094e68193d82736466cf1b0356f78b83..4eb327d41c1d1d8e8b4a0bf5a9155c9a844aadc4 100644
--- a/content/child/child_discardable_shared_memory_manager.h
+++ b/content/child/child_discardable_shared_memory_manager.h
@@ -40,6 +40,11 @@ class CONTENT_EXPORT ChildDiscardableSharedMemoryManager
   void UnlockSpan(DiscardableSharedMemoryHeap::Span* span);
   void ReleaseSpan(scoped_ptr<DiscardableSharedMemoryHeap::Span> span);
 
+  base::trace_event::MemoryAllocatorDump* CreateMemoryAllocatorDump(
+      DiscardableSharedMemoryHeap::Span* span,
+      const char* name,
+      base::trace_event::ProcessMemoryDump* pmd) const;
+
  private:
   scoped_ptr<base::DiscardableSharedMemory>
   AllocateLockedDiscardableSharedMemory(size_t size,