Use a direct include of strings headers in ui/, part 3.

ui/views/controls/button/text_button.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_VIEWS_CONTROLS_BUTTON_TEXT_BUTTON_H_
 #define UI_VIEWS_CONTROLS_BUTTON_TEXT_BUTTON_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/font.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/views/border.h"
 #include "ui/views/controls/button/custom_button.h"
 #include "ui/views/native_theme_delegate.h"
 #include "ui/views/painter.h"
 
 namespace views {
 
@@ skipping 373 matching lines @@
   // True if the button should ignore the minimum size for the platform. Default
   // is true. Set to false to prevent narrower buttons.
   bool ignore_minimum_size_;
 
   DISALLOW_COPY_AND_ASSIGN(TextButton);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_BUTTON_TEXT_BUTTON_H_