components/metrics: Add runtime memory leak detector

third_party/tcmalloc/chromium/src/gperftools/heap-profiler.h

 /* Copyright (c) 2005, 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 113 matching lines @@
  * to the object being visited.
  */
 typedef void (*AddressVisitor)(void* data, const void* ptr);
 
 /* Iterate over all live allocated objects. For each allocation the
  * callback will be invoked with the data argument and allocation pointer.
  */
 PERFTOOLS_DLL_DECL void IterateAllocatedObjects(AddressVisitor callback,
                                                 void* data);
 
+/* Export this dummy function so that the LeakDetector is compiled in. */
+#if defined (ENABLE_LEAK_DETECTOR)
+void LeakDetectorDummy();
+#endif
+
 #ifdef __cplusplus
 }  // extern "C"
 #endif
 
 #endif  /* BASE_HEAP_PROFILER_H_ */