Drag and drop cleans up touch sequences from the source window.

ui/events/gestures/gesture_recognizer_impl_mac.cc

 // 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.
 
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "ui/events/gestures/gesture_recognizer.h"
 
 namespace ui {
@@ skipping 23 matching lines @@
   }
   GestureConsumer* GetTouchLockedTarget(const TouchEvent& event) override {
     return NULL;
   }
   GestureConsumer* GetTargetForLocation(const gfx::PointF& location,
                                         int source_device_id) override {
     return NULL;
   }
   void CancelActiveTouchesExcept(GestureConsumer* not_cancelled) override {}
   void TransferEventsTo(GestureConsumer* current_consumer,
-                        GestureConsumer* new_consumer) override {}
+                        GestureConsumer* new_consumer,
+                        ShouldCancelTouches should_cancel_touches) override {}
   bool GetLastTouchPointForTarget(GestureConsumer* consumer,
                                   gfx::PointF* point) override {
     return false;
   }
   bool CancelActiveTouches(GestureConsumer* consumer) override { return false; }
   void AddGestureEventHelper(GestureEventHelper* helper) override {}
   void RemoveGestureEventHelper(GestureEventHelper* helper) override {}
 
   DISALLOW_COPY_AND_ASSIGN(GestureRecognizerImplMac);
 };
 
 }  // namespace
 
 // static
 GestureRecognizer* GestureRecognizer::Get() {
   CR_DEFINE_STATIC_LOCAL(GestureRecognizerImplMac, instance, ());
   return &instance;
 }
 
 }  // namespace ui