Enable memory profiler when TC_MALLOC is enabled for

third_party/tcmalloc/chromium/src/gperftools/malloc_extension.h

Index: third_party/tcmalloc/chromium/src/gperftools/malloc_extension.h
===================================================================
--- third_party/tcmalloc/chromium/src/gperftools/malloc_extension.h	(revision 148994)
+++ third_party/tcmalloc/chromium/src/gperftools/malloc_extension.h	(working copy)
@@ -1,4 +1,4 @@
-// Copyright (c) 2005, Google Inc.
+// Copyright (c) 2012, Google Inc.
 // All rights reserved.
 // 
 // Redistribution and use in source and binary forms, with or without
@@ -307,6 +307,10 @@
   // malloc implementation during initialization.
   static void Register(MallocExtension* implementation);
 
+  // On the current thread, return the total number of bytes allocated.
+  // (Currently only implemented in tcmalloc.)
+  static unsigned int GetBytesAllocatedOnCurrentThread();
+
   // Returns detailed information about malloc's freelists. For each list,
   // return a FreeListInfo:
   struct FreeListInfo {