Make event-targeting asynchronous in window server.

services/ui/ws/event_dispatcher_delegate.h

 // Copyright 2015 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_DISPATCHER_DELEGATE_H_
 #define SERVICES_UI_WS_EVENT_DISPATCHER_DELEGATE_H_
 
 #include <stdint.h>
 
 #include "services/ui/common/types.h"
@@ skipping 49 matching lines @@
   virtual void OnMouseCursorLocationChanged(const gfx::Point& point,
                                             const int64_t display_id) = 0;
 
   // Dispatches an event to the specific client.
   virtual void DispatchInputEventToWindow(ServerWindow* target,
                                           ClientSpecificId client_id,
                                           const int64_t display_id,
                                           const ui::Event& event,
                                           Accelerator* accelerator) = 0;
 
+  // Starts processing the next event in the event queue.
+  virtual void ProcessNextEventFromQueue() = 0;
+
   // 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,
                                                   bool in_nonclient_area) = 0;
 
   // Returns the window to start searching from at the specified location, or
   // null if there is a no window containing |location_in_display|.
   // |location_in_display| is in display coordinates and in pixels.
   // |location_in_display| and |display_id| are updated if the window we
   // found is on a different display than the originated display.
   // TODO(riajiang): No need to update |location_in_display| and |display_id|
   // after ozone drm can tell us the right display the cursor is on for
   // drag-n-drop events. crbug.com/726470
   virtual ServerWindow* GetRootWindowContaining(gfx::Point* location_in_display,
                                                 int64_t* display_id) = 0;
 
   // Called when event dispatch could not find a target. OnAccelerator may still
   // be called.
   virtual void OnEventTargetNotFound(const ui::Event& event,
                                      const int64_t display_id) = 0;
 
  protected:
   virtual ~EventDispatcherDelegate() {}
 };
 
 }  // namespace ws
 }  // namespace ui
 
 #endif  // SERVICES_UI_WS_EVENT_DISPATCHER_DELEGATE_H_