ServiceWorker: Keep the worker alive until FetchEvent.waitUntil settles

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 2b9ecc9205f9a9a698661ab679ff2e564dea24b6..2128e5702549535db03d472b8b98a56fc55910c5 100644
--- a/content/browser/service_worker/service_worker_fetch_dispatcher.cc
+++ b/content/browser/service_worker/service_worker_fetch_dispatcher.cc
@@ -11,6 +11,7 @@
 #include "content/browser/service_worker/embedded_worker_status.h"
 #include "content/browser/service_worker/service_worker_version.h"
 #include "content/common/service_worker/service_worker_messages.h"
+#include "content/common/service_worker/service_worker_utils.h"
 
 namespace content {
 
@@ -95,13 +96,21 @@ void ServiceWorkerFetchDispatcher::DispatchFetchEvent() {
   base::Closure prepare_callback = prepare_callback_;
   prepare_callback.Run();
 
-  int request_id = version_->StartRequest(
+  int response_id = version_->StartRequest(
       GetEventType(), base::Bind(&ServiceWorkerFetchDispatcher::DidFail,
                                  weak_factory_.GetWeakPtr()));
-  version_->DispatchEvent<ServiceWorkerHostMsg_FetchEventFinished>(
-      request_id, ServiceWorkerMsg_FetchEvent(request_id, *request_.get()),
-      base::Bind(&ServiceWorkerFetchDispatcher::DidFinish,
-                 weak_factory_.GetWeakPtr()));
+  int event_finish_id = version_->StartRequest(
+      ServiceWorkerMetrics::EventType::FETCH_WAITUNTIL,
+      base::Bind(&ServiceWorkerUtils::NoOpStatusCallback));
+
+  version_->RegisterRequestCallback<ServiceWorkerHostMsg_FetchEventResponse>(
+      response_id, base::Bind(&ServiceWorkerFetchDispatcher::DidFinish,
+                              weak_factory_.GetWeakPtr()));
+  version_->RegisterSimpleRequest<ServiceWorkerHostMsg_FetchEventFinished>(
+      event_finish_id);
+  version_->DispatchEvent({response_id, event_finish_id},
+                          ServiceWorkerMsg_FetchEvent(
+                              response_id, event_finish_id, *request_.get()));
 }
 
 void ServiceWorkerFetchDispatcher::DidPrepare() {