Report promise reject with no handler (behind a flag).

src/messages.h

Index: src/messages.h
diff --git a/src/messages.h b/src/messages.h
index aec346903522a87857284652f646e89a82669469..efb39fa1d6cd61274aec9cae1234debfd778f008 100644
--- a/src/messages.h
+++ b/src/messages.h
@@ -68,10 +68,8 @@ class MessageHandler {
  public:
   // Returns a message object for the API to use.
   static Handle<JSMessageObject> MakeMessageObject(
-      Isolate* isolate,
-      const char* type,
-      MessageLocation* loc,
-      Vector< Handle<Object> > args,
+      Isolate* isolate, const char* type, MessageLocation* loc,
+      Vector<Handle<Object> > args, Handle<JSObject> promise,
       Handle<JSArray> stack_frames);
 
   // Report a formatted message (needs JS allocation).