First step to refactor ServiceWorkerVersion to make event dispatching more modular.

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 150 matching lines @@
 void ServiceWorkerMetrics::RecordEventHandledRatio(EventType event,
                                                    size_t handled_events,
                                                    size_t fired_events) {
   if (!fired_events)
     return;
   EventHandledRatioType type = EVENT_HANDLED_SOME;
   if (fired_events == handled_events)
     type = EVENT_HANDLED_ALL;
   else if (handled_events == 0)
     type = EVENT_HANDLED_NONE;
+
   // For now Fetch is the only type that is recorded.
-  DCHECK_EQ(EVENT_TYPE_FETCH, event);
+  if (event != EventType::FETCH)
+    return;
   UMA_HISTOGRAM_ENUMERATION("ServiceWorker.EventHandledRatioType.Fetch", type,
                             NUM_EVENT_HANDLED_RATIO_TYPE);
 }
 
+void ServiceWorkerMetrics::RecordEventTimeout(EventType event) {
+  UMA_HISTOGRAM_ENUMERATION("ServiceWorker.RequestTimeouts.Count",
+                            static_cast<int>(event),
+                            static_cast<int>(EventType::NUM_TYPES));
+}
+
 void ServiceWorkerMetrics::RecordFetchEventStatus(
     bool is_main_resource,
     ServiceWorkerStatusCode status) {
   if (is_main_resource) {
     UMA_HISTOGRAM_ENUMERATION("ServiceWorker.FetchEvent.MainResource.Status",
                               status, SERVICE_WORKER_ERROR_MAX_VALUE);
   } else {
     UMA_HISTOGRAM_ENUMERATION("ServiceWorker.FetchEvent.Subresource.Status",
                               status, SERVICE_WORKER_ERROR_MAX_VALUE);
   }
@@ skipping 46 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