Service Worker: FetchEvent.preventDefault() results in a network error

Source/web/ServiceWorkerGlobalScopeProxy.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 64 matching lines @@
     ASSERT(m_workerGlobalScope);
     WaitUntilObserver* observer = WaitUntilObserver::create(m_workerGlobalScope, WaitUntilObserver::Activate, eventID);
     RefPtrWillBeRawPtr<Event> event(ExtendableEvent::create(EventTypeNames::activate, ExtendableEventInit(), observer));
     m_workerGlobalScope->dispatchExtendableEvent(event.release(), observer);
 }
 
 void ServiceWorkerGlobalScopeProxy::dispatchFetchEvent(int eventID, const WebServiceWorkerRequest& webRequest)
 {
     ASSERT(m_workerGlobalScope);
     RespondWithObserver* observer = RespondWithObserver::create(m_workerGlobalScope, eventID, webRequest.mode(), webRequest.frameType());
+    bool defaultPrevented = false;
     if (!RuntimeEnabledFeatures::serviceWorkerOnFetchEnabled()) {
-        observer->didDispatchEvent();
+        observer->didDispatchEvent(defaultPrevented);
         return;
     }
 
     Request* request = Request::create(m_workerGlobalScope, webRequest);
     request->headers()->setGuard(Headers::ImmutableGuard);
     RefPtrWillBeRawPtr<FetchEvent> fetchEvent(FetchEvent::create(observer, request));
     fetchEvent->setIsReload(webRequest.isReload());
-    m_workerGlobalScope->dispatchEvent(fetchEvent.release());
-    observer->didDispatchEvent();
+    defaultPrevented = !m_workerGlobalScope->dispatchEvent(fetchEvent.release());
+    observer->didDispatchEvent(defaultPrevented);
 }
 
 void ServiceWorkerGlobalScopeProxy::dispatchGeofencingEvent(int eventID, WebGeofencingEventType eventType, const WebString& regionID, const WebCircularGeofencingRegion& region)
 {
     ASSERT(m_workerGlobalScope);
     const AtomicString& type = eventType == WebGeofencingEventTypeEnter ? EventTypeNames::geofenceenter : EventTypeNames::geofenceleave;
     m_workerGlobalScope->dispatchEvent(GeofencingEvent::create(type, regionID, CircularGeofencingRegion::create(regionID, region)));
 }
 
 void ServiceWorkerGlobalScopeProxy::dispatchInstallEvent(int eventID)
@@ skipping 94 matching lines @@
 
 ServiceWorkerGlobalScopeProxy::ServiceWorkerGlobalScopeProxy(WebEmbeddedWorkerImpl& embeddedWorker, Document& document, WebServiceWorkerContextClient& client)
     : m_embeddedWorker(embeddedWorker)
     , m_document(document)
     , m_client(client)
     , m_workerGlobalScope(0)
 {
 }
 
 } // namespace blink