Use fetch_event_id (fetchEventID in blink) for FetchEvent

content/browser/service_worker/service_worker_fetch_dispatcher.cc

Index: content/browser/service_worker/service_worker_fetch_dispatcher.cc
diff --git a/content/browser/service_worker/service_worker_fetch_dispatcher.cc b/content/browser/service_worker/service_worker_fetch_dispatcher.cc
index 601f64fe3806c7c2492ddcac0aeee4405080b862..f3faf3e6af73f9dcafdb91c4e69cd2bdd383b605 100644
--- a/content/browser/service_worker/service_worker_fetch_dispatcher.cc
+++ b/content/browser/service_worker/service_worker_fetch_dispatcher.cc
@@ -207,7 +207,7 @@ void ServiceWorkerFetchDispatcher::DispatchFetchEvent() {
   prepare_callback.Run();
 
   net_log_.BeginEvent(net::NetLogEventType::SERVICE_WORKER_FETCH_EVENT);
-  int response_id = version_->StartRequest(
+  int fetch_event_id = version_->StartRequest(
       GetEventType(),
       base::Bind(&ServiceWorkerFetchDispatcher::DidFailToDispatch,
                  weak_factory_.GetWeakPtr()));
@@ -218,7 +218,7 @@ void ServiceWorkerFetchDispatcher::DispatchFetchEvent() {
   ResponseCallback* response_callback =
       new ResponseCallback(weak_factory_.GetWeakPtr(), version_.get());
   version_->RegisterRequestCallback<ServiceWorkerHostMsg_FetchEventResponse>(
-      response_id,
+      fetch_event_id,
       base::Bind(&ServiceWorkerFetchDispatcher::ResponseCallback::Run,
                  base::Owned(response_callback)));
 
@@ -228,7 +228,7 @@ void ServiceWorkerFetchDispatcher::DispatchFetchEvent() {
   // |dispatcher| is owned by |version_|. So it is safe to pass the unretained
   // raw pointer of |version_| to OnFetchEventFinished callback.
   dispatcher->DispatchFetchEvent(
-      response_id, *request_,
+      fetch_event_id, *request_,
       base::Bind(&OnFetchEventFinished, base::Unretained(version_.get()),
                  event_finish_id));
 }