Introduce ServiceWorker.EventDispatchingDelay UMA

content/browser/service_worker/embedded_worker_test_helper.cc

Index: content/browser/service_worker/embedded_worker_test_helper.cc
diff --git a/content/browser/service_worker/embedded_worker_test_helper.cc b/content/browser/service_worker/embedded_worker_test_helper.cc
index bdefff4ba6194f6735daf324821bba8bce4c6956..1895f336fa0fa5c333798bb4ad1ca20c4f7331d2 100644
--- a/content/browser/service_worker/embedded_worker_test_helper.cc
+++ b/content/browser/service_worker/embedded_worker_test_helper.cc
@@ -12,6 +12,7 @@
 #include "base/bind.h"
 #include "base/memory/scoped_vector.h"
 #include "base/threading/thread_task_runner_handle.h"
+#include "base/time/time.h"
 #include "content/browser/message_port_message_filter.h"
 #include "content/browser/service_worker/embedded_worker_instance.h"
 #include "content/browser/service_worker/embedded_worker_registry.h"
@@ -246,7 +247,8 @@ void EmbeddedWorkerTestHelper::OnFetchEvent(
           blink::WebServiceWorkerResponseErrorUnknown, base::Time(),
           false /* is_in_cache_storage */,
           std::string() /* cache_storage_cache_name */,
-          ServiceWorkerHeaderList() /* cors_exposed_header_names */)));
+          ServiceWorkerHeaderList() /* cors_exposed_header_names */),
+      base::Time::Now()));
   SimulateSend(new ServiceWorkerHostMsg_FetchEventFinished(
       embedded_worker_id, event_finish_id,
       blink::WebServiceWorkerEventResultCompleted));