Use the Navigator's frame in navigator.serviceWorker and associated container.

Source/modules/serviceworkers/NavigatorServiceWorker.h

 // Copyright 2014 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 NavigatorServiceWorker_h
 #define NavigatorServiceWorker_h
 
 #include "bindings/v8/ScriptPromise.h"
 #include "core/frame/Navigator.h"
 #include "heap/Handle.h"
 #include "platform/Supplementable.h"
 
 namespace WebCore {
 
 class Navigator;
 class ServiceWorkerContainer;
 
 class NavigatorServiceWorker FINAL : public NoBaseWillBeGarbageCollectedFinalized<NavigatorServiceWorker>, public WillBeHeapSupplement<Navigator>, DOMWindowProperty {
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(NavigatorServiceWorker);
 public:
     virtual ~NavigatorServiceWorker();
     static NavigatorServiceWorker& from(Navigator&);
     static NavigatorServiceWorker* toNavigatorServiceWorker(Navigator&);
     static const char* supplementName();
 
-    static ServiceWorkerContainer* serviceWorker(ExecutionContext*, Navigator&);
+    static ServiceWorkerContainer* serviceWorker(Navigator&);
 
     void trace(Visitor*) { }
 
 private:
     explicit NavigatorServiceWorker(Navigator&);
-    ServiceWorkerContainer* serviceWorker(ExecutionContext*);
+    ServiceWorkerContainer* serviceWorker();
 
     // DOMWindowProperty override.
     virtual void willDetachGlobalObjectFromFrame() OVERRIDE;
 
     RefPtr<ServiceWorkerContainer> m_serviceWorker;
 };
 
 } // namespace WebCore
 
 #endif // NavigatorServiceWorker_h