ServiceWorker: Keep the worker alive until FetchEvent.waitUntil settles

content/browser/service_worker/service_worker_metrics.cc

Index: content/browser/service_worker/service_worker_metrics.cc
diff --git a/content/browser/service_worker/service_worker_metrics.cc b/content/browser/service_worker/service_worker_metrics.cc
index eaf8071ffa4f87e00f6e4352b14509e80400d36f..b853fa925b2500e2e8caa26fd9972d0e6008bfc4 100644
--- a/content/browser/service_worker/service_worker_metrics.cc
+++ b/content/browser/service_worker/service_worker_metrics.cc
@@ -67,6 +67,8 @@ std::string EventTypeToSuffix(ServiceWorkerMetrics::EventType event_type) {
       return "_UNKNOWN";
     case ServiceWorkerMetrics::EventType::FOREIGN_FETCH:
       return "_FOREIGN_FETCH";
+    case ServiceWorkerMetrics::EventType::FETCH_WAITUNTIL:
+      return "_FETCH_WAITUNTIL";
     case ServiceWorkerMetrics::EventType::NUM_TYPES:
       NOTREACHED() << static_cast<int>(event_type);
   }
@@ -186,6 +188,8 @@ const char* ServiceWorkerMetrics::EventTypeToString(EventType event_type) {
       return "Unknown";
     case EventType::FOREIGN_FETCH:
       return "Foreign Fetch";
+    case EventType::FETCH_WAITUNTIL:
+      return "Fetch WaitUntil";
     case EventType::NUM_TYPES:
       break;
   }
@@ -417,6 +421,10 @@ void ServiceWorkerMetrics::RecordEventDuration(EventType event,
                                    time);
       }
       break;
+    case EventType::FETCH_WAITUNTIL:
+      UMA_HISTOGRAM_MEDIUM_TIMES("ServiceWorker.FetchEvent.WaitUntil.Time",
+                                 time);
+      break;
     case EventType::FOREIGN_FETCH:
       if (was_handled) {
         UMA_HISTOGRAM_MEDIUM_TIMES(