Enumerate the return value of dispatchEvent so it is clear.

third_party/WebKit/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 279 matching lines @@
 
 ServiceWorkerGlobalScope* ServiceWorkerGlobalScopeProxy::workerGlobalScope() const
 {
     ASSERT(m_workerGlobalScope);
     return m_workerGlobalScope;
 }
 
 void ServiceWorkerGlobalScopeProxy::dispatchFetchEventImpl(int eventID, const WebServiceWorkerRequest& webRequest, const AtomicString& eventTypeName)
 {
     RespondWithObserver* observer = RespondWithObserver::create(workerGlobalScope(), eventID, webRequest.url(), webRequest.mode(), webRequest.frameType(), webRequest.requestContext());
-    bool defaultPrevented = false;
     Request* request = Request::create(workerGlobalScope(), webRequest);
     request->headers()->setGuard(Headers::ImmutableGuard);
     FetchEventInit eventInit;
     eventInit.setCancelable(true);
     eventInit.setRequest(request);
     eventInit.setClientId(webRequest.isMainResourceLoad() ? WebString() : webRequest.clientId());
     eventInit.setIsReload(webRequest.isReload());
     RefPtrWillBeRawPtr<FetchEvent> fetchEvent(FetchEvent::create(eventTypeName, eventInit, observer));
-    defaultPrevented = !workerGlobalScope()->dispatchEvent(fetchEvent.release());
-    observer->didDispatchEvent(defaultPrevented);
+    DispatchEventResult dispatchResult = workerGlobalScope()->dispatchEvent(fetchEvent.release());
+    observer->didDispatchEvent(dispatchResult);
 }
 
 } // namespace blink