ServiceWorker: Add initial implementation of ExtendableMessageEvent behind a flag

content/browser/service_worker/service_worker_metrics.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/service_worker/service_worker_metrics.h"
 
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/strings/string_util.h"
 #include "content/common/service_worker/service_worker_types.h"
@@ skipping 211 matching lines @@
       UMA_HISTOGRAM_MEDIUM_TIMES("ServiceWorker.BackgroundSyncEvent.Time",
                                  time);
       break;
     case EventType::NOTIFICATION_CLICK:
       UMA_HISTOGRAM_MEDIUM_TIMES("ServiceWorker.NotificationClickEvent.Time",
                                  time);
       break;
     case EventType::PUSH:
       UMA_HISTOGRAM_MEDIUM_TIMES("ServiceWorker.PushEvent.Time", time);
       break;
+    case EventType::MESSAGE:
+      // TODO(nhiroki): Record event duration for Message event after
+      // ExtendableMessageEvent is enabled by default (crbug.com/543198).
+      break;
 
     // Event duration for fetch is recorded separately.
     case EventType::FETCH:
     // For now event duration for these events is not recorded.
     case EventType::GEOFENCING:
     case EventType::SERVICE_PORT_CONNECT:
-    case EventType::MESSAGE:
       break;
 
     case EventType::NUM_TYPES:
       NOTREACHED() << "Invalid event type";
       break;
   }
 }
 
 void ServiceWorkerMetrics::RecordFetchEventStatus(
     bool is_main_resource,
@@ skipping 54 matching lines @@
   UMA_HISTOGRAM_ENUMERATION("ServiceWorker.URLRequestJob.FallbackedRequestMode",
                             mode, FETCH_REQUEST_MODE_LAST + 1);
 }
 
 void ServiceWorkerMetrics::RecordTimeBetweenEvents(
     const base::TimeDelta& time) {
   UMA_HISTOGRAM_MEDIUM_TIMES("ServiceWorker.TimeBetweenEvents", time);
 }
 
 }  // namespace content