Use a direct include of strings headers, delete some strings forwarding headers.

chrome/browser/ui/webui/options/language_options_handler_common.cc

 // 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 "chrome/browser/ui/webui/options/language_options_handler_common.h"
 
 #include <map>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/prefs/pref_service.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/spellchecker/spellcheck_factory.h"
 #include "chrome/browser/spellchecker/spellcheck_service.h"
 #include "chrome/browser/translate/translate_manager.h"
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/common/chrome_switches.h"
@@ skipping 226 matching lines @@
 }
 
 base::WeakPtr<SpellcheckHunspellDictionary>&
     LanguageOptionsHandlerCommon::GetHunspellDictionary() {
   if (!hunspell_dictionary_.get())
     RefreshHunspellDictionary();
   return hunspell_dictionary_;
 }
 
 }  // namespace options