onScheduleMessagePumpWork

Called from any thread when work has been scheduled for the browser process main (UI) thread. This callback should schedule a CefApp.DoMessageLoopWork() call to happen on the main (UI) thread. |delay_ms| is the requested delay in milliseconds. If |delay_ms| is <= 0 then the call should happen reasonably soon. If |delay_ms| is >0 then the call should be scheduled to happen after the specified delay and any currently pending scheduled call should be cancelled.