Enumerate the return value of dispatchEvent so it is clear.

third_party/WebKit/Source/modules/serviceworkers/RespondWithObserver.cpp

 // 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.
 
 #include "modules/serviceworkers/RespondWithObserver.h"
 
 #include "bindings/core/v8/ScriptFunction.h"
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptValue.h"
 #include "bindings/core/v8/V8Binding.h"
@@ skipping 127 matching lines @@
 {
     return new RespondWithObserver(context, eventID, requestURL, requestMode, frameType, requestContext);
 }
 
 void RespondWithObserver::contextDestroyed()
 {
     ContextLifecycleObserver::contextDestroyed();
     m_state = Done;
 }
 
-void RespondWithObserver::didDispatchEvent(bool defaultPrevented)
+void RespondWithObserver::didDispatchEvent(DispatchEventResult dispatchResult)
 {
     ASSERT(executionContext());
     if (m_state != Initial)
         return;
 
-    if (defaultPrevented) {
+    if (dispatchResult != DispatchEventResult::NotCanceled) {
         responseWasRejected(WebServiceWorkerResponseErrorDefaultPrevented);
         return;
     }
 
     ServiceWorkerGlobalScopeClient::from(executionContext())->didHandleFetchEvent(m_eventID);
     m_state = Done;
 }
 
 void RespondWithObserver::respondWith(ScriptState* scriptState, ScriptPromise scriptPromise, ExceptionState& exceptionState)
 {
@@ skipping 95 matching lines @@
     , m_state(Initial)
 {
 }
 
 DEFINE_TRACE(RespondWithObserver)
 {
     ContextLifecycleObserver::trace(visitor);
 }
 
 } // namespace blink