Use a direct include of strings headers in chrome/browser/chromeos/.

chrome/browser/chromeos/login/default_user_images.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_BROWSER_CHROMEOS_LOGIN_DEFAULT_USER_IMAGES_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_DEFAULT_USER_IMAGES_H_
 
 #include <cstddef>  // for size_t
 #include <string>
 
-#include "base/string16.h"
+#include "base/strings/string16.h"
 
 namespace gfx {
 class ImageSkia;
 }
 
 namespace chromeos {
 
 // Returns path to default user image with specified index.
 // The path is used in Local State to distinguish default images.
 // This function is obsolete and is preserved only for compatibility with older
@@ skipping 55 matching lines @@
 
 // Number of possible histogram values for user images.
 extern const int kHistogramImagesCount;
 
 // Returns the histogram value corresponding to the given default image index.
 int GetDefaultImageHistogramValue(int index);
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_DEFAULT_USER_IMAGES_H_