service worker: Attribute purpose to start worker attempts for UMA

content/browser/service_worker/service_worker_dispatcher_host.cc

 // Copyright 2013 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/service_worker/service_worker_dispatcher_host.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "base/macros.h"
@@ skipping 860 matching lines @@
     const base::string16& message,
     const url::Origin& source_origin,
     const std::vector<TransferredMessagePort>& sent_message_ports,
     const SourceInfo& source_info) {
   if (!source_info.IsValid()) {
     DidFailToDispatchExtendableMessageEvent(sent_message_ports,
                                             SERVICE_WORKER_ERROR_FAILED);
     return;
   }
   worker->RunAfterStartWorker(
+      ServiceWorkerMetrics::EventType::MESSAGE,
       base::Bind(&ServiceWorkerDispatcherHost::
                      DispatchExtendableMessageEventAfterStartWorker,
                  this, worker, message, source_origin, sent_message_ports,
                  ExtendableMessageEventSource(source_info)),
       base::Bind(
           &ServiceWorkerDispatcherHost::DidFailToDispatchExtendableMessageEvent,
           this, sent_message_ports));
 }
 
 void ServiceWorkerDispatcherHost::
@@ skipping 498 matching lines @@
   if (!handle) {
     bad_message::ReceivedBadMessage(this,
                                     bad_message::SWDH_TERMINATE_BAD_HANDLE);
     return;
   }
   handle->version()->StopWorker(
       base::Bind(&ServiceWorkerUtils::NoOpStatusCallback));
 }
 
 }  // namespace content