Use a direct include of strings headers in webkit/, part 1.

webkit/base/origin_url_conversions.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 WEBKIT_BASE_ORIGIN_URL_CONVERSIONS_H_
 #define WEBKIT_BASE_ORIGIN_URL_CONVERSIONS_H_
 
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "webkit/base/webkit_base_export.h"
 
 class GURL;
 
 namespace webkit_base {
 
 // Returns the origin url for the given |identifier| and vice versa.
 // The origin identifier string is a serialized form of a security origin
 // and can be used as a path name as it contains no "/" or other possibly
 // unsafe characters. (See WebKit's SecurityOrigin code for more details.)
 //
 // Example:
 //   "http://www.example.com:80/"'s identifier should look like:
 //   "http_www.example.host_80"
 WEBKIT_BASE_EXPORT GURL GetOriginURLFromIdentifier(
     const base::string16& identifier);
 
 WEBKIT_BASE_EXPORT base::string16 GetOriginIdentifierFromURL(const GURL& url);
 
 }  // namespace webkit_base
 
 #endif  // WEBKIT_BASE_ORIGIN_URL_CONVERSIONS_H_