[VSync Queue] Plug touch ack to gesture events and flush vsync queue if necessary

content/browser/renderer_host/input/passthrough_touch_event_queue.h

 // Copyright 2017 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_PASSTHROUGH_TOUCH_EVENT_QUEUE_H_
 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_PASSTHROUGH_TOUCH_EVENT_QUEUE_H_
 
 #include "content/browser/renderer_host/input/touch_event_queue.h"
 
 #include <set>
@@ skipping 37 matching lines @@
   bool IsPendingAckTouchStart() const override;
 
   void SetAckTimeoutEnabled(bool enabled) override;
 
   void SetIsMobileOptimizedSite(bool mobile_optimized_site) override;
 
   bool IsAckTimeoutEnabled() const override;
 
   bool Empty() const override;
 
+  bool SendTouchEventsAsync() const override;
+
  protected:
   void SendTouchCancelEventForTouchEvent(
       const TouchEventWithLatencyInfo& event_to_cancel) override;
   void UpdateTouchConsumerStates(const blink::WebTouchEvent& event,
                                  InputEventAckState ack_result) override;
   // Empties the queue of touch events. This may result in any number of gesture
   // events being sent to the renderer.
   void FlushQueue() override;
 
  private:
@@ skipping 67 matching lines @@
   // not yet been ack'd by the renderer. The set is explicitly ordered based
   // on the unique touch event id.
   std::set<TouchEventWithLatencyInfoAndAckState> outstanding_touches_;
 
   DISALLOW_COPY_AND_ASSIGN(PassthroughTouchEventQueue);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_PASSTHROUGH_TOUCH_EVENT_QUEUE_H_