Signal input flush when all flings have terminated

content/browser/renderer_host/input/gesture_event_queue.h

 // Copyright 2014 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_GESTURE_EVENT_QUEUE_H_
 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_GESTURE_EVENT_QUEUE_H_
 
 #include <deque>
 
 #include "base/basictypes.h"
@@ skipping 75 matching lines @@
   // immediately.
   void QueueEvent(const GestureEventWithLatencyInfo&);
 
   // Indicates that the caller has received an acknowledgement from the renderer
   // with state |ack_result| and event |type|. May send events if the queue is
   // not empty.
   void ProcessGestureAck(InputEventAckState ack_result,
                          blink::WebInputEvent::Type type,
                          const ui::LatencyInfo& latency);
 
-  // Sets the state of the |fling_in_progress_| field to indicate that a fling
-  // is definitely not in progress.
-  void FlingHasBeenHalted();
+  // Notify the queue that a gesture fling animation in the renderer has ended.
+  void DidStopFlinging();
 
   // Returns the |TouchpadTapSuppressionController| instance.
   TouchpadTapSuppressionController* GetTouchpadTapSuppressionController();
 
   void ForwardGestureEvent(const GestureEventWithLatencyInfo& gesture_event);
 
   bool empty() const {
     return coalesced_gesture_events_.empty() &&
            debouncing_deferral_queue_.empty();
   }
 
+  int active_fling_count() const { return active_fling_count_; }
+
   void set_debounce_interval_time_ms_for_testing(int interval_ms) {
     debounce_interval_ = base::TimeDelta::FromMilliseconds(interval_ms);
   }
 
  private:
   friend class GestureEventQueueTest;
   friend class MockRenderWidgetHost;
 
   // TODO(mohsen): There are a bunch of ShouldForward.../ShouldDiscard...
   // methods that are getting confusing. This should be somehow fixed. Maybe
@@ skipping 31 matching lines @@
   void QueueScrollOrPinchAndForwardIfNecessary(
       const GestureEventWithLatencyInfo& gesture_event);
 
   // The number of sent events for which we're awaiting an ack.  These events
   // remain at the head of the queue until ack'ed.
   size_t EventsInFlightCount() const;
 
   // The receiver of all forwarded gesture events.
   GestureEventQueueClient* client_;
 
-  // True if a GestureFlingStart is in progress on the renderer or
-  // queued without a subsequent queued GestureFlingCancel event.
-  bool fling_in_progress_;
+  // Whether there are any active flings in the renderer. As the fling
+  // end notification is asynchronous, we use a count rather than a boolean
+  // to avoid races in bookkeeping when starting a new fling.
+  int active_fling_count_;
 
   // True if a GestureScrollUpdate sequence is in progress.
   bool scrolling_in_progress_;
 
   // True if two related gesture events were sent before without waiting
   // for an ACK, so the next gesture ACK should be ignored.
   bool ignore_next_ack_;
 
   // An object tracking the state of touchpad on the delivery of mouse events to
   // the renderer to filter mouse immediately after a touchpad fling canceling
@@ skipping 26 matching lines @@
   // Time window in which to debounce scroll/fling ends. Note that an interval
   // of zero effectively disables debouncing.
   base::TimeDelta debounce_interval_;
 
   DISALLOW_COPY_AND_ASSIGN(GestureEventQueue);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_GESTURE_EVENT_QUEUE_H_