Clean forward declaration in public

public/platform/WebServiceWorkerProvider.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 17 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef WebServiceWorkerProvider_h
 #define WebServiceWorkerProvider_h
 
 #include "public/platform/WebCallbacks.h"
 
 namespace blink {
 
-class WebString;
 class WebURL;
 class WebServiceWorker;
 class WebServiceWorkerProviderClient;
 class WebServiceWorkerRegistration;
 struct WebServiceWorkerError;
 
 // Created on the main thread, and may be passed to another script context
 // thread (e.g. worker thread) later. All methods of this class must be called
 // on the single script context thread.
 class WebServiceWorkerProvider {
@@ skipping 14 matching lines @@
     virtual void unregisterServiceWorker(const WebURL& pattern, WebServiceWorkerUnregistrationCallbacks*) { }
 
     virtual void getRegistration(const WebURL& documentURL, WebServiceWorkerGetRegistrationCallbacks*) { }
 
     virtual ~WebServiceWorkerProvider() { }
 };
 
 } // namespace blink
 
 #endif