Move WindowImpl to gfx so I can use it there for canvas unit tests....

gfx/window_impl.h

 // Copyright (c) 2010 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 APP_WIN_WINDOW_IMPL_H_
-#define APP_WIN_WINDOW_IMPL_H_
+#ifndef GFX_WINDOW_IMPL_H_
+#define GFX_WINDOW_IMPL_H_
 
 #include <atlbase.h>
 #include <atlapp.h>
 #include <atlmisc.h>
 #include <atlcrack.h>
 
 #include <string>
 
 #include "base/logging.h"
 #include "gfx/native_widget_types.h"
 #include "gfx/rect.h"
 
-namespace app {
+namespace gfx {
 
 // An interface implemented by classes that use message maps.
 // ProcessWindowMessage is implemented by the BEGIN_MESSAGE_MAP_EX macro.
 class MessageMapInterface {
  public:
   // Processes one message from the window's message queue.
   virtual BOOL ProcessWindowMessage(HWND window,
                                     UINT message,
                                     WPARAM w_param,
                                     LPARAM l_param,
@@ skipping 71 matching lines @@
 
   // Style of the class to use.
   UINT class_style_;
 
   // Our hwnd.
   HWND hwnd_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowImpl);
 };
 
-}  // namespace app
+}  // namespace gfx
 
-#endif  // APP_WIN_WINDOW_IMPL_H_
+#endif  // GFX_WINDOW_IMPL_H_