Merge "audiomanager: fix volume group callback" am: bb10358a

            Handler handler = eventHandler.handler();

            if (handler != null) {

                Message m = handler.obtainMessage(what, arg1, arg2, obj);

                if (what != AUDIOVOLUMEGROUP_EVENT_NEW_LISTENER) {

                    handler.removeMessages(what);

                }

                // Do not remove previous messages, as we would lose notification of group changes

                handler.sendMessage(m);

            }

        }