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

Source/modules/serviceworkers/NavigatorServiceWorker.h

Index: Source/modules/serviceworkers/NavigatorServiceWorker.h
diff --git a/Source/modules/serviceworkers/NavigatorServiceWorker.h b/Source/modules/serviceworkers/NavigatorServiceWorker.h
index 57f114def8015809f4b2641bd9af728c367d9b7b..c9937317d0ef66181a545cc0dd984aa1ceb06d7c 100644
--- a/Source/modules/serviceworkers/NavigatorServiceWorker.h
+++ b/Source/modules/serviceworkers/NavigatorServiceWorker.h
@@ -23,13 +23,13 @@ public:
     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;