Explicit interface for synchronous InputHandlerProxy input handling

content/renderer/gpu/input_event_filter.h

Index: content/renderer/gpu/input_event_filter.h
diff --git a/content/renderer/gpu/input_event_filter.h b/content/renderer/gpu/input_event_filter.h
index 9e9481936f2d801c444b9e28c63b6ae68df28973..693aefa9e575b2a1800e654937e950d4b3702bb3 100644
--- a/content/renderer/gpu/input_event_filter.h
+++ b/content/renderer/gpu/input_event_filter.h
@@ -28,22 +28,19 @@ namespace content {
 class CONTENT_EXPORT InputEventFilter
     : public IPC::ChannelProxy::MessageFilter {
  public:
-  typedef base::Callback<void(int /*routing_id*/,
-                              const WebKit::WebInputEvent*)> Handler;
+  typedef base::Callback<InputEventAckState(
+      int /*routing_id*/,
+      const WebKit::WebInputEvent*)> Handler;
 
   // The |handler| is invoked on the thread associated with |target_loop| to
-  // handle input events matching the filtered routes.  In response, the
-  // handler should call either DidHandleInputEvent or DidNotHandleInputEvent.
-  // These may be called asynchronously to the handler invocation, but they
-  // must be called on the target thread.
+  // handle input events matching the filtered routes.
   //
-  // If DidNotHandleInputEvent is called with send_to_widget set to true, then
+  // If INPUT_EVENT_ACK_STATE_NOT_CONSUMED is returned by the handler,
   // the original InputMsg_HandleInputEvent message will be delivered to
   // |main_listener| on the main thread.  (The "main thread" in this context is
-  // the thread where the InputEventFilter was constructed.)  If send_to_widget
-  // is true, then a InputHostMsg_HandleInputEvent_ACK will not be
-  // generated, leaving that responsibility up to the eventual handler on the
-  // main thread.
+  // the thread where the InputEventFilter was constructed.)  The responsibility
+  // is left to the eventual handler to deliver the corresponding
+  // InputHostMsg_HandleInputEvent_ACK.
   //
   InputEventFilter(IPC::Listener* main_listener,
                    const scoped_refptr<base::MessageLoopProxy>& target_loop,
@@ -53,10 +50,6 @@ class CONTENT_EXPORT InputEventFilter
   void AddRoute(int routing_id);
   void RemoveRoute(int routing_id);
 
-  // Called on the target thread by the Handler.
-  void DidHandleInputEvent();
-  void DidNotHandleInputEvent(bool send_to_widget);
-
   // IPC::ChannelProxy::MessageFilter methods:
   virtual void OnFilterAdded(IPC::Channel* channel) OVERRIDE;
   virtual void OnFilterRemoved() OVERRIDE;
@@ -86,7 +79,6 @@ class CONTENT_EXPORT InputEventFilter
   // The handler_ only gets Run on the thread corresponding to target_loop_.
   scoped_refptr<base::MessageLoopProxy> target_loop_;
   Handler handler_;
-  std::queue<IPC::Message> messages_;
 
   // Protects access to routes_.
   base::Lock routes_lock_;