Stop sending an async touchmove for the app slop region

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 186 matching lines @@
 
   // Used to defer touch forwarding when ack dispatch triggers |QueueEvent()|.
   // If not NULL, |dispatching_touch_ack_| is the touch event of which the ack
   // is being dispatched.
   const CoalescedWebTouchEvent* dispatching_touch_ack_;
 
   // Used to prevent touch timeout scheduling if we receive a synchronous
   // ack after forwarding a touch event to the client.
   bool dispatching_touch_;
 
+  // Whether we're in the scope of a |ProcessTouchAck| call. Used to defer
+  // sending async touchmove's, avoiding contention with touch ack side-effects.
+  bool processing_touch_ack_;
+
   // Whether the renderer has at least one touch handler.
   bool has_handlers_;
 
   // Whether to allow any remaining touches for the current sequence. Note that
   // this is a stricter condition than an empty |touch_consumer_states_|, as it
   // also prevents forwarding of touchstart events for new pointers in the
   // current sequence. This is only used when the event is synthetically
   // cancelled after a touch timeout, or after a scroll event when the
   // mode is TOUCH_SCROLLING_MODE_TOUCHCANCEL.
   bool drop_remaining_touches_in_sequence_;
@@ skipping 19 matching lines @@
   // setting for experimentation, but we may evolve it into an app-controlled
   // mode.
   const TouchScrollingMode touch_scrolling_mode_;
 
   DISALLOW_COPY_AND_ASSIGN(TouchEventQueue);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_EVENT_QUEUE_H_