Move Aura to UI subdir.

ui/aura/desktop_host.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 AURA_DESKTOP_HOST_H_
-#define AURA_DESKTOP_HOST_H_
+#ifndef UI_AURA_DESKTOP_HOST_H_
+#define UI_AURA_DESKTOP_HOST_H_
 #pragma once
 
 #include "base/message_loop.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace gfx {
 class Rect;
 class Size;
 }
 
@@ skipping 20 matching lines @@
   // Shows the DesktopHost.
   virtual void Show() = 0;
 
   // Gets/Sets the size of the DesktopHost.
   virtual gfx::Size GetSize() = 0;
   virtual void SetSize(const gfx::Size& size) = 0;
 };
 
 }  // namespace aura
 
-#endif  // AURA_DESKTOP_HOST_H_
+#endif  // UI_AURA_DESKTOP_HOST_H_