Use a direct include of strings headers in chrome/renderer/.

chrome/renderer/spellchecker/spellcheck_language.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 CHROME_RENDERER_SPELLCHECKER_SPELLCHECK_LANGUAGE_H_
 #define CHROME_RENDERER_SPELLCHECKER_SPELLCHECK_LANGUAGE_H_
 
 #include <queue>
 #include <string>
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/platform_file.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "chrome/renderer/spellchecker/spellcheck_worditerator.h"
 
 class SpellingEngine;
 
 class SpellcheckLanguage {
  public:
   SpellcheckLanguage();
   ~SpellcheckLanguage();
 
   void Init(base::PlatformFile file, const std::string& language);
@@ skipping 42 matching lines @@
   SpellcheckWordIterator contraction_iterator_;
 
   // Pointer to a platform-specific spelling engine, if it is in use. This
   // should only be set if hunspell is not used. (I.e. on OSX, for now)
   scoped_ptr<SpellingEngine> platform_spelling_engine_;
 
   DISALLOW_COPY_AND_ASSIGN(SpellcheckLanguage);
 };
 
 #endif  // CHROME_RENDERER_SPELLCHECKER_SPELLCHECK_LANGUAGE_H_