Send touch cancel to renderer when scrolling starts

content/browser/renderer_host/input/touch_event_queue.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_TOUCH_EVENT_QUEUE_H_
 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EVENT_QUEUE_H_
 
 #include <deque>
 #include <map>
 
@@ skipping 34 matching lines @@
   // single touch-move event). The event may also be immediately forwarded to
   // the renderer (e.g. when there are no other queued touch event).
   void QueueEvent(const TouchEventWithLatencyInfo& event);
 
   // Notifies the queue that a touch-event has been processed by the renderer.
   // At this point, the queue may send one or more gesture events and/or
   // additional queued touch-events to the renderer.
   void ProcessTouchAck(InputEventAckState ack_result,
                        const ui::LatencyInfo& latency_info);
 
+  void OnGestureScrollEvent(const GestureEventWithLatencyInfo& gesture_event);
+
   // Empties the queue of touch events. This may result in any number of gesture
   // events being sent to the renderer.
   void FlushQueue();
 
   // Returns whether the event-queue is empty.
   bool empty() const WARN_UNUSED_RESULT {
     return touch_queue_.empty();
   }
 
-  void set_no_touch_move_to_renderer(bool value) {
-    no_touch_move_to_renderer_ = value;
-  }
-
  private:
   friend class MockRenderWidgetHost;
   friend class ImmediateInputRouterTest;
 
   CONTENT_EXPORT size_t GetQueueSize() const;
   CONTENT_EXPORT const TouchEventWithLatencyInfo& GetLatestEvent() const;
 
   // Pops the touch-event from the top of the queue and sends it to the
   // TouchEventQueueClient. This reduces the size of the queue by one.
   void PopTouchEventToClient(InputEventAckState ack_result,
                              const ui::LatencyInfo& renderer_latency_info);
 
   bool ShouldForwardToRenderer(const WebKit::WebTouchEvent& event) const;
 
   // Handles touch event forwarding and ack'ed event dispatch.
   TouchEventQueueClient* client_;
 
   typedef std::deque<CoalescedWebTouchEvent*> TouchQueue;
   TouchQueue touch_queue_;
 
   // Maintain the ACK status for each touch point.
   typedef std::map<int, InputEventAckState> TouchPointAckStates;
   TouchPointAckStates touch_ack_states_;
 
   // Used to defer touch forwarding when ack dispatch triggers |QueueEvent()|.
   bool dispatching_touch_ack_;
 
-  // Don't send touch move events to renderer. This is enabled when the page
-  // is scrolling. This behaviour is currently enabled only on aura behind a
-  // flag.
-  bool no_touch_move_to_renderer_;
+  // Don't send touch events to renderer. This is enabled when the page
+  // is scrolling. This behaviour is currently enabled only on aura behind
+  // a flag.
+  bool no_touch_to_renderer_;
+
+  // Latest event that is queued.
+  TouchEventWithLatencyInfo latest_event_;

[sadrul, 2013/09/23 16:17:33]

Why do you need this?

+
+  // When scroll begins, we send the |synthesized_cancel_event_| to renderer
+  // and when it is acked back we drop it before forwarding it to view.
+  CoalescedWebTouchEvent* synthesized_cancel_event_;

[sadrul, 2013/09/23 16:17:33]

We shouldn't hold onto a raw pointer like this. Add some attribute on
CoalescedWebTouchEvent that carries this information instead.

 
   DISALLOW_COPY_AND_ASSIGN(TouchEventQueue);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EVENT_QUEUE_H_