service worker: Attribute purpose to start worker attempts for UMA

content/browser/service_worker/service_worker_job_unittest.cc

Index: content/browser/service_worker/service_worker_job_unittest.cc
diff --git a/content/browser/service_worker/service_worker_job_unittest.cc b/content/browser/service_worker/service_worker_job_unittest.cc
index 0cbe471ff32e2fafb6306c3d7753174092f05b6f..f1175b27ae004323682ff37d7ed1cb1039447d67 100644
--- a/content/browser/service_worker/service_worker_job_unittest.cc
+++ b/content/browser/service_worker/service_worker_job_unittest.cc
@@ -643,7 +643,8 @@ TEST_F(ServiceWorkerJobTest, UnregisterWaitingSetsRedundant) {
   scoped_refptr<ServiceWorkerVersion> version = new ServiceWorkerVersion(
       registration.get(), script_url, 1L, helper_->context()->AsWeakPtr());
   ServiceWorkerStatusCode status = SERVICE_WORKER_ERROR_FAILED;
-  version->StartWorker(CreateReceiverOnCurrentThread(&status));
+  version->StartWorker(ServiceWorkerMetrics::EventType::UNKNOWN,
+                       CreateReceiverOnCurrentThread(&status));
   base::RunLoop().RunUntilIdle();
   ASSERT_EQ(SERVICE_WORKER_OK, status);
 
@@ -1420,7 +1421,8 @@ class EventCallbackHelper : public EmbeddedWorkerTestHelper {
   void set_activate_event_result(blink::WebServiceWorkerEventResult result) {
     activate_event_result_ = result;
   }
-private:
+
+ private:
   base::Closure install_callback_;
   blink::WebServiceWorkerEventResult install_event_result_;
   blink::WebServiceWorkerEventResult activate_event_result_;