service worker: Attribute purpose to start worker attempts for UMA

content/browser/background_sync/background_sync_manager.cc

 // Copyright 2015 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/background_sync/background_sync_manager.h"
 
 #include <utility>
 
 #include "base/barrier_closure.h"
 #include "base/bind.h"
@@ skipping 692 matching lines @@
 void BackgroundSyncManager::DispatchSyncEvent(
     const std::string& tag,
     const scoped_refptr<ServiceWorkerVersion>& active_version,
     BackgroundSyncEventLastChance last_chance,
     const ServiceWorkerVersion::StatusCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK(active_version);
 
   if (active_version->running_status() != ServiceWorkerVersion::RUNNING) {
     active_version->RunAfterStartWorker(
+        ServiceWorkerMetrics::EventType::SYNC,
         base::Bind(&BackgroundSyncManager::DispatchSyncEvent,
                    weak_ptr_factory_.GetWeakPtr(), tag, active_version,
                    last_chance, callback),
         callback);
     return;
   }
 
   int request_id = active_version->StartRequestWithCustomTimeout(
       ServiceWorkerMetrics::EventType::SYNC, callback,
       parameters_->max_sync_event_duration,
@@ skipping 484 matching lines @@
 BackgroundSyncManager::MakeStatusCompletion(const StatusCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
   return base::Bind(
       &BackgroundSyncManager::CompleteOperationCallback<StatusCallback,
                                                         BackgroundSyncStatus>,
       weak_ptr_factory_.GetWeakPtr(), callback);
 }
 
 }  // namespace content