Use a direct include of strings headers in x/.

chrome/browser/ui/views/ssl_client_certificate_selector.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_UI_VIEWS_SSL_CLIENT_CERTIFICATE_SELECTOR_H_
 #define CHROME_BROWSER_UI_VIEWS_SSL_CLIENT_CERTIFICATE_SELECTOR_H_
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "chrome/browser/ssl/ssl_client_auth_observer.h"
 #include "chrome/browser/ssl/ssl_client_certificate_selector.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/controls/table/table_view_observer.h"
 #include "ui/views/view.h"
 #include "ui/views/window/dialog_delegate.h"
 
 // This header file exists only for testing.  Chrome should access the
 // certificate selector only through the cross-platform interface
 // chrome/browser/ssl_client_certificate_selector.h.
@@ skipping 59 matching lines @@
   content::WebContents* web_contents_;
 
   views::Widget* window_;
   views::TableView* table_;
   views::LabelButton* view_cert_button_;
 
   DISALLOW_COPY_AND_ASSIGN(SSLClientCertificateSelector);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_SSL_CLIENT_CERTIFICATE_SELECTOR_H_