Release aura::Desktop event handler windows on detaching an ancestor window.

ui/aura/window.h

 // Copyright (c) 2011 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_H_
 #define UI_AURA_WINDOW_H_
 #pragma once
 
 #include <map>
 #include <string>
@@ skipping 128 matching lines @@
   bool CanActivate() const;
 
   // Tree operations.
   // TODO(beng): Child windows are currently not owned by the hierarchy. We
   //             should change this.
   void AddChild(Window* child);
   void RemoveChild(Window* child);
 
   const Windows& children() const { return children_; }
 
+  // Returns true if this Window contains |other| somewhere in its children.
+  bool Contains(const Window* other) const;
+
   // Adds or removes |child| as a transient child of this window. Transient
   // children get the following behavior:
   // . The transient parent destroys any transient children when it is
   //   destroyed. This means a transient child is destroyed if either its parent
   //   or transient parent is destroyed.
   // . If a transient child and its transient parent share the same parent, then
   //   transient children are always ordered above the trasient parent.
   // Transient windows are typically used for popups and menus.
   void AddTransientChild(Window* child);
   void RemoveTransientChild(Window* child);
@@ skipping 180 matching lines @@
   // TODO(oshima): Consolidcate ViewProp and aura::window property
   // implementation.
   std::map<const char*, void*> prop_map_;
 
   DISALLOW_COPY_AND_ASSIGN(Window);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_H_