Mikhail, or can we get registered events from application storage first? I mean if there is onSuspend event in event list, we send the event to render process and wait for the acknowledge callback. Otherwise, we suppose no onSuspend event is registered and close the main document immediately. 

One concern of this method is about the onSupend event handler inside main page. If the handler is time wasting, ApplicationProcessManager has to wait until the handler finishes the code logic. 
WDYT?