Don't send touch move to renderer while scrolling

content/browser/renderer_host/touch_event_queue.h

Index: content/browser/renderer_host/touch_event_queue.h
diff --git a/content/browser/renderer_host/touch_event_queue.h b/content/browser/renderer_host/touch_event_queue.h
index 8c2a1ad2d0c979e4bcf5774509eef153e4a82f00..5df235bdd3a9d465783102d935f37d873c4d1c72 100644
--- a/content/browser/renderer_host/touch_event_queue.h
+++ b/content/browser/renderer_host/touch_event_queue.h
@@ -37,6 +37,12 @@ class TouchEventQueue {
   // additional queued touch-events to the renderer.
   void ProcessTouchAck(InputEventAckState ack_result);
 
+  // On receiving the first GestureScrollUpdate, flushes any touch events in
+  // the queue to view, sends a touch cancel event to the renderer immediately,
+  // and then resets the event queue so as not to process the acked touch cancel
+  // event.
+  void OnGestureScrollStart();
+
   // Empties the queue of touch events. This may result in any number of gesture
   // events being sent to the renderer.
   void FlushQueue();
@@ -68,6 +74,8 @@ class TouchEventQueue {
   typedef std::deque<CoalescedWebTouchEvent*> TouchQueue;
   TouchQueue touch_queue_;
 
+  TouchEventWithLatencyInfo latest_event_;
+
   // Maintain the ACK status for each touch point.
   typedef std::map<int, InputEventAckState> TouchPointAckStates;
   TouchPointAckStates touch_ack_states_;