ServiceWorker: Factor out FetchEvent related logics from RespondWithObserver.

third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp

Index: third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp
diff --git a/third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp b/third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp
index 77df99ec57b377fd1ce1b346d619c5c82849c293..73f863cb305a2a19c97bfdb01695a4e72f3ac4e2 100644
--- a/third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp
+++ b/third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp
@@ -164,10 +164,11 @@ void ServiceWorkerGlobalScopeProxy::dispatchFetchEvent(
       workerGlobalScope()->scriptController()->getScriptState());
   WaitUntilObserver* waitUntilObserver = WaitUntilObserver::create(
       workerGlobalScope(), WaitUntilObserver::Fetch, fetchEventID);
-  RespondWithObserver* respondWithObserver = RespondWithObserver::create(
-      workerGlobalScope(), fetchEventID, webRequest.url(), webRequest.mode(),
-      webRequest.redirectMode(), webRequest.frameType(),
-      webRequest.requestContext(), waitUntilObserver);
+  FetchRespondWithObserver* respondWithObserver =
+      FetchRespondWithObserver::create(
+          workerGlobalScope(), fetchEventID, webRequest.url(),
+          webRequest.mode(), webRequest.redirectMode(), webRequest.frameType(),
+          webRequest.requestContext(), waitUntilObserver);
   Request* request = Request::create(
       workerGlobalScope()->scriptController()->getScriptState(), webRequest);
   request->getHeaders()->setGuard(Headers::ImmutableGuard);