ui/base: Move message_box_win.{h,cc} to ui/base/win.

ui/base/win/message_box_win.cc

Index: ui/base/win/message_box_win.cc
diff --git a/ui/base/message_box_win.cc b/ui/base/win/message_box_win.cc
similarity index 86%
rename from ui/base/message_box_win.cc
rename to ui/base/win/message_box_win.cc
index 622a9d8e7809bab4050aea9d79460241f45e840d..c78e98baf667782ffa0037d066dad2a074471fdb 100644
--- a/ui/base/message_box_win.cc
+++ b/ui/base/win/message_box_win.cc
@@ -1,15 +1,12 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
-#include "ui/base/message_box_win.h"
+#include "ui/base/win/message_box_win.h"
 
-#include <windows.h>
-
-#include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/i18n/rtl.h"
-#include "base/string16.h"
+#include "ui/base/ui_base_switches.h"
 
 namespace ui {