Update to Chromium //base at Chromium commit 3e81715e6d3a4324362635aea46ce1f1a163cca1.

memory/discardable_memory.h

 // Copyright (c) 2013 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_MEMORY_DISCARDABLE_MEMORY_H_
 #define BASE_MEMORY_DISCARDABLE_MEMORY_H_
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 
 namespace base {
 
+namespace trace_event {
+class MemoryAllocatorDump;
+class ProcessMemoryDump;
+}
+
 // Discardable memory is used to cache large objects without worrying about
 // blowing out memory, both on mobile devices where there is no swap, and
 // desktop devices where unused free memory should be used to help the user
 // experience. This is preferable to releasing memory in response to an OOM
 // signal because it is simpler and provides system-wide management of
 // purgable memory, though it has less flexibility as to which objects get
 // discarded.
 //
 // Discardable memory has two states: locked and unlocked. While the memory is
 // locked, it will not be discarded. Unlocking the memory allows the
@@ skipping 28 matching lines @@
   virtual void Unlock() = 0;
 
   // Returns the memory address held by this object. The object must be locked
   // before calling this.
   virtual void* data() const = 0;
 
   // Handy method to simplify calling data() with a reinterpret_cast.
   template<typename T> T* data_as() const {
     return reinterpret_cast<T*>(data());
   }
+
+  // Used for dumping the statistics of discardable memory allocated in tracing.
+  // Returns a new MemoryAllocatorDump in the |pmd| with the size of the
+  // discardable memory. The MemoryAllocatorDump created is owned by |pmd|. See
+  // ProcessMemoryDump::CreateAllocatorDump.
+  virtual trace_event::MemoryAllocatorDump* CreateMemoryAllocatorDump(
+      const char* name,
+      trace_event::ProcessMemoryDump* pmd) const = 0;
 };
 
 }  // namespace base
 
 #endif  // BASE_MEMORY_DISCARDABLE_MEMORY_H_