aura: Destroy the compositor before destroying the backing window.

ui/gfx/win/window_impl.h

 // Copyright (c) 2012 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_GFX_WIN_WINDOW_IMPL_H_
 #define UI_GFX_WIN_WINDOW_IMPL_H_
 
 #include <atlbase.h>
 #include <atlapp.h>
 #include <atlmisc.h>
@@ skipping 36 matching lines @@
 
   // Initializes the Window with a parent and an initial desired size.
   void Init(HWND parent, const gfx::Rect& bounds);
 
   // Returns the default window icon to use for windows of this type.
   virtual HICON GetDefaultWindowIcon() const;
 
   // Returns the HWND associated with this Window.
   HWND hwnd() const { return hwnd_; }
 
+  // Marks the window as destroyed, setting the hwnd to NULL.
+  void SetDestroyed();
+
   // Sets the window styles. This is ONLY used when the window is created.
   // In other words, if you invoke this after invoking Init, nothing happens.
   void set_window_style(DWORD style) { window_style_ = style; }
   DWORD window_style() const { return window_style_; }
 
   // Sets the extended window styles. See comment about |set_window_style|.
   void set_window_ex_style(DWORD style) { window_ex_style_ = style; }
   DWORD window_ex_style() const { return window_ex_style_; }
 
   // Sets the class style to use. The default is CS_DBLCLKS.
@@ skipping 47 matching lines @@
   bool got_create_;
   bool got_valid_hwnd_;
   bool* destroyed_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowImpl);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_WIN_WINDOW_IMPL_H_