Report DOM partitionAlloc size to V8 GC.

Source/platform/Partitions.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 17 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "platform/Partitions.h"
 
 namespace WebCore {
 
 SizeSpecificPartitionAllocator<3072> Partitions::m_objectModelAllocator;
 SizeSpecificPartitionAllocator<1024> Partitions::m_renderingAllocator;
+size_t Partitions::m_domMemoryUsage = 0;
 
 void Partitions::init()
 {
     m_objectModelAllocator.init();
     m_renderingAllocator.init();
+    m_domMemoryUsage = 0;
 }
 
 void Partitions::shutdown()
 {
     // We could ASSERT here for a memory leak within the partition, but it leads
     // to very hard to diagnose ASSERTs, so it's best to leave leak checking for
     // the valgrind and heapcheck bots, which run without partitions.
     (void) m_renderingAllocator.shutdown();
     (void) m_objectModelAllocator.shutdown();
 }
 
 } // namespace WebCore