Make event-targeting asynchronous in window server.

services/ui/ws/event_targeter_delegate.h

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SERVICES_UI_WS_EVENT_TARGETER_DELEGATE_H_
 #define SERVICES_UI_WS_EVENT_TARGETER_DELEGATE_H_
 
 #include <stdint.h>
 
 namespace gfx {
 class Point;
 }
 
 namespace ui {
 namespace ws {
 class ServerWindow;
 
 // Used by EventTargeter to talk to WindowManagerState.
 class EventTargeterDelegate {
  public:
   // Calls EventDispatcherDelegate::GetRootWindowContaining, see
   // event_dispatcher_delegate.h for details.
   virtual ServerWindow* GetRootWindowContaining(gfx::Point* location_in_display,
                                                 int64_t* display_id) = 0;
 
+  // Calls EventDispatcherDelegate::ProcessNextAvailableEvent, see
+  // event_dispatcher_delegate.h for details.
+  virtual void ProcessNextAvailableEvent() = 0;
+
  protected:
   virtual ~EventTargeterDelegate() {}
 };
 
 }  // namespace ws
 }  // namespace ui
 
 #endif  // SERVICES_UI_WS_EVENT_TARGETER_DELEGATE_H_