Make event-targeting asynchronous in window server.

services/ui/ws/event_dispatcher_delegate.h

Index: services/ui/ws/event_dispatcher_delegate.h
diff --git a/services/ui/ws/event_dispatcher_delegate.h b/services/ui/ws/event_dispatcher_delegate.h
index 69b7a1b40ee9d39917bf6703ce2d321111ae48c1..c496c122ffed8416a4b2457c71f42e034fb29bfb 100644
--- a/services/ui/ws/event_dispatcher_delegate.h
+++ b/services/ui/ws/event_dispatcher_delegate.h
@@ -63,6 +63,8 @@ class EventDispatcherDelegate {
                                           const ui::Event& event,
                                           Accelerator* accelerator) = 0;
 
+  virtual void ProcessNextEventFromQueue() = 0;

[sky, 2017/05/22 16:06:56]

Add description.

[riajiang, 2017/05/29 23:38:07]

Done.

+
   // Returns the id of the client to send events to. |in_nonclient_area| is
   // true if the event occurred in the non-client area of the window.
   virtual ClientSpecificId GetEventTargetClientId(const ServerWindow* window,