Provided batched input delivery with a BufferedInputRouter

content/browser/renderer_host/input/input_router_client.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_BROWSER_RENDERER_HOST_INPUT_INPUT_ROUTER_CLIENT_H_
 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_INPUT_ROUTER_CLIENT_H_
 
 #include "content/common/content_export.h"
 #include "content/port/browser/event_with_latency_info.h"
 #include "content/port/common/input_event_ack_state.h"
@@ skipping 44 matching lines @@
   virtual bool OnSendGestureEvent(
       const GestureEventWithLatencyInfo& gesture_event) = 0;
   virtual bool OnSendMouseEventImmediately(
       const MouseEventWithLatencyInfo& mouse_event) = 0;
   virtual bool OnSendTouchEventImmediately(
       const TouchEventWithLatencyInfo& touch_event) = 0;
   virtual bool OnSendGestureEventImmediately(
       const GestureEventWithLatencyInfo& gesture_event) = 0;
 
   // Called upon event ack receipt from the renderer.
   virtual void OnKeyboardEventAck(const NativeWebKeyboardEvent& event,

[aelias_OOO_until_Jul13, 2013/08/13 06:11:51]

I think these should be moved into "InputAckHandler" base class.  Make
RenderWidgetHostImpl derive from InputAckHandler (not BufferedInputRouter).  And
make the methods have a return value like:

  scoped_ptr_vector<InputEvent> OnGestureEventAck(const WebGestureEvent&,
InputEventAckState);

Then the BufferedInputRouter/InputQueue would inject those returned input events
(if any) at the right part of the queue.

[jdduke (slow), 2013/08/13 15:29:48]

I would love for this to be the case.  As it stands that may take a good amount
of wiring (getting things out of the GR), but having an explicit followup adds a
lot of clarity.

                                   InputEventAckState ack_result) = 0;
   virtual void OnWheelEventAck(const WebKit::WebMouseWheelEvent& event,
                                InputEventAckState ack_result) = 0;
   virtual void OnTouchEventAck(const TouchEventWithLatencyInfo& event,
                                InputEventAckState ack_result) = 0;
   virtual void OnGestureEventAck(const WebKit::WebGestureEvent& event,
                                  InputEventAckState ack_result) = 0;
   virtual void OnUnexpectedEventAck(bool bad_message) = 0;
+
+  // Certain router implementations require periodic flushing of queued events.
+  // When this method is called, the client should ensure a timely call, either
+  // synchronous or asynchronous, of |Flush| on the InputRouter.
+  virtual void SetNeedsFlush() = 0;
+
+  // Called when the router has finished flushing all events queued at the time
+  // of the call to Flush.  The call will typically be asynchronous with
+  // respect to the call to |Flush| on the InputRouter.
+  virtual void DidFlush() = 0;
 };
 
 } // namespace content
 
 #endif // CONTENT_BROWSER_RENDERER_HOST_INPUT_INPUT_ROUTER_CLIENT_H_