Use a direct include of strings headers in ui/, part 1.

ui/base/ime/character_composer.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_IME_CHARACTER_COMPOSER_H_
 #define UI_BASE_IME_CHARACTER_COMPOSER_H_
 
 #include <vector>
 
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "ui/base/ui_export.h"
 
 namespace ui {
 
 // A class to recognize compose and dead key sequence.
 // Outputs composed character.
 class UI_EXPORT CharacterComposer {
  public:
   CharacterComposer();
   ~CharacterComposer();
@@ skipping 60 matching lines @@
 
   // Composition mode which this instance is in.
   CompositionMode composition_mode_;
 
   DISALLOW_COPY_AND_ASSIGN(CharacterComposer);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_IME_CHARACTER_COMPOSER_H_