Fix for default value of FetchEvent.cancellable

Source/web/ServiceWorkerGlobalScopeProxy.cpp

Index: Source/web/ServiceWorkerGlobalScopeProxy.cpp
diff --git a/Source/web/ServiceWorkerGlobalScopeProxy.cpp b/Source/web/ServiceWorkerGlobalScopeProxy.cpp
index a756bfdcf1cf90c5636824f36a7e2c8788f51299..288c100ca45b82a11eb761e744ef23bce2836d5b 100644
--- a/Source/web/ServiceWorkerGlobalScopeProxy.cpp
+++ b/Source/web/ServiceWorkerGlobalScopeProxy.cpp
@@ -105,6 +105,7 @@ void ServiceWorkerGlobalScopeProxy::dispatchFetchEvent(int eventID, const WebSer
     Request* request = Request::create(m_workerGlobalScope, webRequest);
     request->headers()->setGuard(Headers::ImmutableGuard);
     FetchEventInit eventInit;
+    eventInit.setCancelable(true);
     eventInit.setRequest(request);
     eventInit.setIsReload(webRequest.isReload());
     RefPtrWillBeRawPtr<FetchEvent> fetchEvent(FetchEvent::create(EventTypeNames::fetch, eventInit, observer));