Use a direct include of strings headers in ui/, part 2.

ui/base/win/hwnd_util.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_BASE_WIN_HWND_UTIL_H_
 #define UI_BASE_WIN_HWND_UTIL_H_
 
 #include <windows.h>
 
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "ui/base/ui_export.h"
 
 namespace gfx {
 class Point;
 class Size;
 }
 
 namespace ui {
 
 // A version of the GetClassNameW API that returns the class name in an
@@ skipping 27 matching lines @@
 UI_EXPORT void ShowSystemMenuAtPoint(HWND window, const gfx::Point& point);
 
 // Returns the window you can use to parent a top level window.
 // Note that in some cases we create child windows not parented to its final
 // container so in those cases you should pass true in |get_real_hwnd|.
 UI_EXPORT HWND GetWindowToParentTo(bool get_real_hwnd);
 
 }  // namespace ui
 
 #endif  // UI_BASE_WIN_HWND_UTIL_H_