Implicit references are missing in heap profiles

src/heap.h

Index: src/heap.h
===================================================================
--- src/heap.h	(revision 13465)
+++ src/heap.h	(working copy)
@@ -1196,15 +1196,6 @@
       GCEpilogueCallback callback, GCType gc_type_filter);
   void RemoveGCEpilogueCallback(GCEpilogueCallback callback);
 
-  void SetGlobalGCPrologueCallback(GCCallback callback) {
-    ASSERT((callback == NULL) ^ (global_gc_prologue_callback_ == NULL));
-    global_gc_prologue_callback_ = callback;
-  }
-  void SetGlobalGCEpilogueCallback(GCCallback callback) {
-    ASSERT((callback == NULL) ^ (global_gc_epilogue_callback_ == NULL));
-    global_gc_epilogue_callback_ = callback;
-  }
-
   // Heap root getters.  We have versions with and without type::cast() here.
   // You can't use type::cast during GC because the assert fails.
   // TODO(1490): Try removing the unchecked accessors, now that GC marking does
@@ -1638,14 +1629,9 @@
 
   inline Isolate* isolate();
 
-  inline void CallGlobalGCPrologueCallback() {
-    if (global_gc_prologue_callback_ != NULL) global_gc_prologue_callback_();
-  }
+  void CallGCPrologueCallbacks(GCType gc_type);
+  void CallGCEpilogueCallbacks(GCType gc_type);
 
-  inline void CallGlobalGCEpilogueCallback() {
-    if (global_gc_epilogue_callback_ != NULL) global_gc_epilogue_callback_();
-  }
-
   inline bool OldGenerationAllocationLimitReached();
 
   inline void DoScavengeObject(Map* map, HeapObject** slot, HeapObject* obj) {
@@ -1936,9 +1922,6 @@
   };
   List<GCEpilogueCallbackPair> gc_epilogue_callbacks_;
 
-  GCCallback global_gc_prologue_callback_;
-  GCCallback global_gc_epilogue_callback_;
-
   // Support for computing object sizes during GC.
   HeapObjectCallback gc_safe_size_of_old_object_;
   static int GcSafeSizeOfOldObject(HeapObject* object);