Introduce ServiceWorker.EventDispatchingDelay UMA

third_party/WebKit/public/platform/modules/background_sync/background_sync.mojom

 // 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.
 
 module blink.mojom;
 
 import "third_party/WebKit/public/platform/modules/serviceworker/service_worker_event_status.mojom";
 
 enum BackgroundSyncNetworkState {
   ANY,
@@ skipping 30 matching lines @@
 };
 
 interface BackgroundSyncService {
   Register(SyncRegistration options, int64 service_worker_registration_id)
       => (BackgroundSyncError err, SyncRegistration options);
   GetRegistrations(int64 service_worker_registration_id)
       => (BackgroundSyncError err, array<SyncRegistration> registrations);
 };
 
 interface BackgroundSyncServiceClient {
+  // TODO(horo): Use mojo.common.mojom.Time for |dispatch_event_time|. It is
+  // using double as the UTC time in seconds, counted from January 1, 1970.
   Sync(string tag, BackgroundSyncEventLastChance last_chance)
-      => (ServiceWorkerEventStatus status);
+      => (ServiceWorkerEventStatus status, double dispatch_event_time);
 };