Add a UseCounter that measures the amount of memory used in PartitionAlloc

Source/wtf/WTF.h

 /*
  * 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 19 matching lines @@
 
 #ifndef WTF_h
 #define WTF_h
 
 #include "wtf/Compiler.h"
 #include "wtf/CurrentTime.h"
 #include "wtf/WTFExport.h"
 
 namespace WTF {
 
+typedef void(*HistogramEnumerationFunction)(const char* name, int sample, int boundaryValue);
+
 // This function must be called exactly once from the main thread before using anything else in WTF.
-WTF_EXPORT void initialize(TimeFunction currentTimeFunction, TimeFunction monotonicallyIncreasingTimeFunction);
+WTF_EXPORT void initialize(TimeFunction currentTimeFunction, TimeFunction monotonicallyIncreasingTimeFunction, HistogramEnumerationFunction);
 WTF_EXPORT void shutdown();
 WTF_EXPORT bool isShutdown();
 
 } // namespace WTF
 
 #endif // WTF_h