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

chrome/test/chromedriver/key_converter.h

 // Copyright (c) 2013 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_TEST_CHROMEDRIVER_KEY_CONVERTER_H_
 #define CHROME_TEST_CHROMEDRIVER_KEY_CONVERTER_H_
 
 #include <list>
 #include <string>
 
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "ui/base/keycodes/keyboard_codes.h"
 
 struct KeyEvent;
 class Status;
 
 // Convenience functions for creating |KeyEvent|s. Used by unittests.
 KeyEvent CreateKeyDownEvent(ui::KeyboardCode key_code, int modifiers);
 KeyEvent CreateKeyUpEvent(ui::KeyboardCode key_code, int modifiers);
 KeyEvent CreateCharEvent(const std::string& unmodified_text,
                          const std::string& modified_text,
                          int modifiers);
 
 // Converts keys into appropriate |KeyEvent|s. This will do a best effort
 // conversion. However, if the input is invalid it will return a status with
 // an error message. If |release_modifiers| is true, all modifiers would be
 // depressed. |modifiers| acts both an input and an output, however, only when
 // the conversion process is successful will |modifiers| be changed.
 Status ConvertKeysToKeyEvents(const string16& keys,
                               bool release_modifiers,
                               int* modifiers,
                               std::list<KeyEvent>* key_events);
 
 #endif  // CHROME_TEST_CHROMEDRIVER_KEY_CONVERTER_H_