ExtendStorageStub added, it is aimed for extending objects backing store when it runs out of space.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index d88240d370db6e49f265a137e6ce1fcec69d202b..7ea72c5bcc2747c8ae3b289f3705b04bcdf540c4 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2537,10 +2537,6 @@ class JSObject: public JSReceiver {
                                   Handle<Name> name,
                                   Handle<Object> old_value);
 
-  static void MigrateToNewProperty(Handle<JSObject> object,
-                                   Handle<Map> transition,
-                                   Handle<Object> value);
-
  private:
   friend class DictionaryElementsAccessor;
   friend class JSReceiver;