Store the id of a contributing motion event in GestureEventData

ui/events/gesture_detection/gesture_provider.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 UI_EVENTS_GESTURE_DETECTION_GESTURE_PROVIDER_H_
 #define UI_EVENTS_GESTURE_DETECTION_GESTURE_PROVIDER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/events/gesture_detection/gesture_detection_export.h"
@@ skipping 66 matching lines @@
   const ui::MotionEvent* current_down_event() const {
     return current_down_event_.get();
   }
 
  private:
   void InitGestureDetectors(const Config& config);
 
   bool CanHandle(const MotionEvent& event) const;
 
   void Fling(base::TimeTicks time,
+             int motion_event_id,

[jdduke (slow), 2014/04/03 15:47:54]

Hmm, can we have Fling take a const MotionEvent& arg? Then we can have
EndTouchScrollIfNecessary also take a const MotionEvent& arg.

[tdresser, 2014/04/03 18:09:47]

Done.

              float x,
              float y,
              float velocity_x,
              float velocity_y);
   void Send(const GestureEventData& gesture);
   void SendTapCancelIfNecessary(const MotionEvent& event);
+  void SendTapCancelIfNecessary(const GestureEventData& event);
   bool SendLongTapIfNecessary(const MotionEvent& event);
   void EndTouchScrollIfNecessary(base::TimeTicks time,
+                                 int motion_event_id,
                                  bool send_scroll_end_event);
 
   GestureProviderClient* const client_;
 
   class GestureListenerImpl;
   friend class GestureListenerImpl;
   scoped_ptr<GestureListenerImpl> gesture_listener_;
 
   class ScaleGestureListenerImpl;
   friend class ScaleGestureListenerImpl;
@@ skipping 17 matching lines @@
 
   // Keeps track of the current GESTURE_LONG_PRESS event. If a context menu is
   // opened after a GESTURE_LONG_PRESS, this is used to insert a
   // GESTURE_TAP_CANCEL for removing any ::active styling.
   base::TimeTicks current_longpress_time_;
 };
 
 }  //  namespace ui
 
 #endif  // UI_EVENTS_GESTURE_DETECTION_GESTURE_PROVIDER_H_