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

src/debug.h

Index: src/debug.h
diff --git a/src/debug.h b/src/debug.h
index a5119d0773946ef4c6302375ab51fba6675de510..edef5a5c9757fac761b89ee4b5790d5986cd94a8 100644
--- a/src/debug.h
+++ b/src/debug.h
@@ -345,7 +345,7 @@ class Debug {
   // Debug event triggers.
   void OnDebugBreak(Handle<Object> break_points_hit, bool auto_continue);
 
-  void OnThrow(Handle<Object> exception, bool uncaught);
+  void OnThrow(Handle<Object> exception, Handle<Object> promise, bool uncaught);
   void OnPromiseReject(Handle<JSObject> promise, Handle<Object> value);
   void OnCompileError(Handle<Script> script);
   void OnBeforeCompile(Handle<Script> script);
@@ -529,9 +529,6 @@ class Debug {
   // Mirror cache handling.
   void ClearMirrorCache();
 
-  // Returns a promise if the pushed try-catch handler matches the current one.
-  bool PromiseHasRejectHandler(Handle<JSObject> promise);
-
   void CallEventCallback(v8::DebugEvent event,
                          Handle<Object> exec_state,
                          Handle<Object> event_data,