Don't use PostTask queueing between compositor and main thread.

content/renderer/input/input_handler_manager.h

 // Copyright 2013 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 CONTENT_RENDERER_INPUT_INPUT_HANDLER_MANAGER_H_
 #define CONTENT_RENDERER_INPUT_INPUT_HANDLER_MANAGER_H_
 
 #include "base/containers/scoped_ptr_hash_map.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 93 matching lines @@
   void ObserveWheelEventAndResultOnCompositorThread(
       int routing_id,
       const blink::WebMouseWheelEvent& wheel_event,
       const cc::InputHandlerScrollResult& scroll_result);
 
   void ObserveGestureEventAndResultOnCompositorThread(
       int routing_id,
       const blink::WebGestureEvent& gesture_event,
       const cc::InputHandlerScrollResult& scroll_result);
 
-  void NotifyInputEventHandledOnCompositorThread(int routing_id,
-                                                 blink::WebInputEvent::Type,
-                                                 InputEventAckState);
-
   typedef base::ScopedPtrHashMap<int,  // routing_id
                                  std::unique_ptr<InputHandlerWrapper>>
       InputHandlerMap;
   InputHandlerMap input_handlers_;
 
   const scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   InputHandlerManagerClient* const client_;
   // May be null.
   SynchronousInputHandlerProxyClient* const synchronous_handler_proxy_client_;
   scheduler::RendererScheduler* const renderer_scheduler_;  // Not owned.
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_INPUT_INPUT_HANDLER_MANAGER_H_