Simplify WebServiceWorker{Registration}Proxy interfaces.

Source/modules/serviceworkers/ServiceWorker.cpp

 /*
  * 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 223 matching lines @@
 void ServiceWorker::stop()
 {
     setProxyState(ContextStopped);
 }
 
 PassRefPtrWillBeRawPtr<ServiceWorker> ServiceWorker::getOrCreate(ExecutionContext* executionContext, WebType* outerWorker)
 {
     if (!outerWorker)
         return nullptr;
 
-    WebServiceWorkerProxy* proxy = outerWorker->proxy();
-    ServiceWorker* existingServiceWorker = proxy ? proxy->unwrap() : 0;
+    ServiceWorker* existingServiceWorker = static_cast<ServiceWorker*>(outerWorker->proxy());
     if (existingServiceWorker) {
         ASSERT(existingServiceWorker->executionContext() == executionContext);
         return existingServiceWorker;
     }
 
     RefPtrWillBeRawPtr<ServiceWorker> worker = adoptRefWillBeNoop(new ServiceWorker(executionContext, adoptPtr(outerWorker)));
     worker->suspendIfNeeded();
     return worker.release();
 }
 
 ServiceWorker::ServiceWorker(ExecutionContext* executionContext, PassOwnPtr<WebServiceWorker> worker)
     : AbstractWorker(executionContext)
-    , WebServiceWorkerProxy(this)
     , m_outerWorker(worker)
     , m_proxyState(Initial)
 {
     ASSERT(m_outerWorker);
     m_outerWorker->setProxy(this);
 }
 
 } // namespace blink