Implement a heap profiler for the Dart managed heap.

runtime/include/dart_api.h

Index: runtime/include/dart_api.h
diff --git a/runtime/include/dart_api.h b/runtime/include/dart_api.h
index 7453f24c8a29b39b5752ab0ed0ef182df305189d..9ab8c681dd54e94619c0ec0d3cbdfc077be6f72d 100755
--- a/runtime/include/dart_api.h
+++ b/runtime/include/dart_api.h
@@ -314,7 +314,7 @@ DART_EXPORT Dart_Handle Dart_NewWeakReferenceSet(Dart_Handle* keys,
                                                  Dart_Handle* values,
                                                  intptr_t num_values);
 
-// --- Garbage Collection Callbacks --
+// --- Garbage Collection Callbacks ---
 
 /**
  * Callbacks signal the beginning and end of a garbage collection.
@@ -384,6 +384,29 @@ DART_EXPORT Dart_Handle Dart_AddGcEpilogueCallback(
 DART_EXPORT Dart_Handle Dart_RemoveGcEpilogueCallback(
     Dart_GcEpilogueCallback callback);
 
+// --- Heap Profiler ---
+
+/**
+ * A callback invoked by the heap profiler during profiling to write
+ * data.
+ */
+typedef void (*Dart_HeapProfileWriteCallback)(const void* data,
+                                              intptr_t length,
+                                              void* stream);
+
+/**
+ * Generates a heap profile.
+ *
+ * \param callback A function pointer that will be repeatedly invoked
+ *   with heap profile data.
+ * \param stream A pointer that will be passed to the callback.  This
+ *   is a convenient way to provide an open stream to the callback.
+ *
+ * \return Success if the heap profile is successful.
+ */
+DART_EXPORT Dart_Handle Dart_HeapProfile(Dart_HeapProfileWriteCallback callback,
+                                         void* stream);
+
 // --- Initialization and Globals ---
 
 /**