MouseWheelEventQueue should respect ScrollBegin/End state from RenderWidgetHost.

content/browser/renderer_host/input/mock_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_MOCK_INPUT_ROUTER_CLIENT_H_
 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_MOCK_INPUT_ROUTER_CLIENT_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 18 matching lines @@
   void IncrementInFlightEventCount(
       blink::WebInputEvent::Type event_type) override;
   void DecrementInFlightEventCount(InputEventAckSource ack_source) override;
   void OnHasTouchEventHandlers(bool has_handlers) override;
   void DidFlush() override;
   void DidOverscroll(const ui::DidOverscrollParams& params) override;
   void DidStopFlinging() override;
   void ForwardGestureEventWithLatencyInfo(
       const blink::WebGestureEvent& gesture_event,
       const ui::LatencyInfo& latency_info) override;
+  bool IsInGestureScroll(blink::WebGestureDevice device) const override;
 
   bool GetAndResetFilterEventCalled();
   size_t GetAndResetDidFlushCount();
   ui::DidOverscrollParams GetAndResetOverscroll();
 
   void set_input_router(InputRouter* input_router) {
     input_router_ = input_router;
   }
 
   bool has_touch_handler() const { return has_touch_handler_; }
   void set_filter_state(InputEventAckState filter_state) {
     filter_state_ = filter_state;
   }
   int in_flight_event_count() const {
     return in_flight_event_count_;
   }
   void set_allow_send_event(bool allow) {
     filter_state_ = INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS;
   }
   const blink::WebInputEvent* last_filter_event() const {
     return last_filter_event_->web_event.get();
   }
 
  private:
   InputRouter* input_router_;
   int in_flight_event_count_;
   bool has_touch_handler_;
+  bool is_in_gesture_scroll_;
 
   InputEventAckState filter_state_;
 
   bool filter_input_event_called_;
   std::unique_ptr<InputEvent> last_filter_event_;
 
   size_t did_flush_called_count_;
 
   ui::DidOverscrollParams overscroll_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_MOCK_INPUT_ROUTER_CLIENT_H_