service worker: Attribute purpose to start worker attempts for UMA

content/browser/navigator_connect/navigator_connect_context_impl.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/navigator_connect/navigator_connect_context_impl.h"
 
 #include <stdint.h>
 
 #include "base/stl_util.h"
 #include "content/browser/message_port_service.h"
@@ skipping 140 matching lines @@
   Port& service_port = ports_[service_port_id];
   service_port.service_worker_registration_id = registration->id();
   service_port.service_worker_registration_origin =
       registration->pattern().GetOrigin();
 
   active_version->RunAfterStartWorker(
       base::Bind(&NavigatorConnectContextImpl::DispatchConnectEvent, this,
                  callback, client_port_id, service_port_id, registration,
                  make_scoped_refptr(active_version)),
       base::Bind(&NavigatorConnectContextImpl::OnConnectError, this, callback,
-                 client_port_id, service_port_id));
+                 client_port_id, service_port_id),
+      ServiceWorkerMetrics::EventType::SERVICE_PORT_CONNECT);
 }
 
 void NavigatorConnectContextImpl::DispatchConnectEvent(
     const ConnectCallback& callback,
     int client_port_id,
     int service_port_id,
     const scoped_refptr<ServiceWorkerRegistration>& service_worker_registration,
     const scoped_refptr<ServiceWorkerVersion>& worker) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK(ContainsKey(ports_, client_port_id));
@@ skipping 86 matching lines @@
   DCHECK(active_version);
 
   const Port& port = ports_[port_id];
   NavigatorConnectClient client(port.target_url, port.client_origin, port_id);
   active_version->DispatchCrossOriginMessageEvent(
       client, message, sent_message_ports,
       base::Bind(&ServiceWorkerUtils::NoOpStatusCallback));
 }
 
 }  // namespace content