Record Chrome trace events in tcmalloc heap profiles

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
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 # endif
 #endif
 
 /* All this code should be usable from within C apps. */
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /* Start profiling and arrange to write profile data to file names
  * of the form: "prefix.0000", "prefix.0001", ...
+ *
+ * If |prefix| is NULL then dumps will not be written to disk. Applications
+ * can use GetHeapProfile() to get profile data, but HeapProfilerDump() will do
+ * nothing.
  */
 PERFTOOLS_DLL_DECL void HeapProfilerStart(const char* prefix);
 
+/* Start profiling with a callback function that returns application-generated
+ * pseudo-stacks. Profiles are not written to disk, but may be obtained via
+ * GetHeapProfile(). In the callback the caller must provide a |stack| buffer
+ * of at least size 32 * sizeof(void*). The callback must return the number of
+ * items copied or zero.
+ */
+typedef int (*PseudoStackGenerator)(void** stack);
+PERFTOOLS_DLL_DECL void HeapProfilerWithPseudoStackStart(
+    PseudoStackGenerator callback);
+
 /* Returns non-zero if we are currently profiling the heap.  (Returns
  * an int rather than a bool so it's usable from C.)  This is true
  * between calls to HeapProfilerStart() and HeapProfilerStop(), and
  * also if the program has been run with HEAPPROFILER, or some other
  * way to turn on whole-program profiling.
  */
 int IsHeapProfilerRunning();
 
 /* Stop heap profiling.  Can be restarted again with HeapProfilerStart(),
  * but the currently accumulated profiling information will be cleared.
@@ skipping 23 matching lines @@
  * callback will be invoked with the data argument and allocation pointer.
  */
 PERFTOOLS_DLL_DECL void IterateAllocatedObjects(AddressVisitor callback,
                                                 void* data);
 
 #ifdef __cplusplus
 }  // extern "C"
 #endif
 
 #endif  /* BASE_HEAP_PROFILER_H_ */