Use a direct include of strings headers in chromeos/.

chromeos/ime/input_method_delegate.h

 // Copyright 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 CHROMEOS_IME_INPUT_METHOD_DELEGATE_H_
 #define CHROMEOS_IME_INPUT_METHOD_DELEGATE_H_
 
 #include <string>
 
 #include "base/basictypes.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 
 namespace chromeos {
 namespace input_method {
 
 // Provides access to read/persist Input Method-related properties.
 class InputMethodDelegate {
  public:
   InputMethodDelegate() {}
   virtual ~InputMethodDelegate() {}
 
@@ skipping 12 matching lines @@
       const std::string& language_code) const = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(InputMethodDelegate);
 };
 
 }  // namespace input_method
 }  // namespace chromeos
 
 #endif  // CHROMEOS_IME_INPUT_METHOD_DELEGATE_H_