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

ui/events/gesture_detection/gesture_provider.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 "ui/events/gesture_detection/gesture_provider.h"
 
 #include <stddef.h>
 
 #include <cmath>
 
@@ skipping 684 matching lines @@
 }
 
 GestureProvider::~GestureProvider() {
 }
 
 bool GestureProvider::OnTouchEvent(const MotionEvent& event) {
   TRACE_EVENT1("input",
                "GestureProvider::OnTouchEvent",
                "action",
                GetMotionEventActionName(event.GetAction()));
-
   DCHECK_NE(0u, event.GetPointerCount());
 
   if (!CanHandle(event))
     return false;
 
   OnTouchEventHandlingBegin(event);
   gesture_listener_->OnTouchEvent(event);
   OnTouchEventHandlingEnd(event);
   uma_histogram_.RecordTouchEvent(event);
   return true;
@@ skipping 114 matching lines @@
   // null'ing of the listener until the sequence has ended.
   if (current_down_event_)
     return;
 
   const bool double_tap_enabled =
       double_tap_support_for_page_ && double_tap_support_for_platform_;
   gesture_listener_->SetDoubleTapEnabled(double_tap_enabled);
 }
 
 }  //  namespace ui