Use a direct include of strings headers in content/p*/.

content/public/browser/web_ui_controller.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 CONTENT_PUBLIC_BROWSER_WEB_UI_CONTROLLER_H_
 #define CONTENT_PUBLIC_BROWSER_WEB_UI_CONTROLLER_H_
 
 #include "base/basictypes.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "content/common/content_export.h"
 
 class GURL;
 
 namespace base {
 class ListValue;
 }
 
 namespace content {
 
@@ skipping 23 matching lines @@
 
   WebUI* web_ui() const { return web_ui_; }
 
  private:
   WebUI* web_ui_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_WEB_UI_CONTROLLER_H_