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

ui/aura/window_event_dispatcher.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_AURA_WINDOW_EVENT_DISPATCHER_H_
 #define UI_AURA_WINDOW_EVENT_DISPATCHER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 179 matching lines @@
   bool CanDispatchToTarget(ui::EventTarget* target) override;
   ui::EventDispatchDetails PreDispatchEvent(ui::EventTarget* target,
                                             ui::Event* event) override;
   ui::EventDispatchDetails PostDispatchEvent(ui::EventTarget* target,
                                              const ui::Event& event) override;
 
   // Overridden from ui::GestureEventHelper.
   bool CanDispatchToConsumer(ui::GestureConsumer* consumer) override;
   void DispatchGestureEvent(ui::GestureConsumer* raw_input_consumer,
                             ui::GestureEvent* event) override;
-  void DispatchCancelTouchEvent(ui::GestureConsumer* raw_input_consumer,
-                                ui::TouchEvent* event) override;
+  void DispatchSyntheticTouchEvent(ui::TouchEvent* event) override;
 
   // Overridden from WindowObserver:
   void OnWindowDestroying(Window* window) override;
   void OnWindowDestroyed(Window* window) override;
   void OnWindowAddedToRootWindow(Window* window) override;
   void OnWindowRemovingFromRootWindow(Window* window,
                                       Window* new_root) override;
   void OnWindowVisibilityChanging(Window* window, bool visible) override;
   void OnWindowVisibilityChanged(Window* window, bool visible) override;
   void OnWindowBoundsChanged(Window* window,
@@ skipping 66 matching lines @@
 
   // Used to schedule DispatchHeldEvents() when |move_hold_count_| goes to 0.
   base::WeakPtrFactory<WindowEventDispatcher> held_event_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowEventDispatcher);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_EVENT_DISPATCHER_H_