[OnionSoup] Move background_sync.mojom from //content to //third_party/WebKit

content/common/background_sync_service.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 content.mojom;
-
-import "content/public/common/background_sync.mojom";
-import "content/public/common/service_worker_event_status.mojom";
-
-enum BackgroundSyncError {
-  NONE,
-  STORAGE,
-  NOT_FOUND,
-  NO_SERVICE_WORKER,
-  NOT_ALLOWED,
-  PERMISSION_DENIED,
-  MAX=PERMISSION_DENIED
-};
-
-enum BackgroundSyncState {
-  PENDING,
-  FIRING,
-  REREGISTERED_WHILE_FIRING,
-};
-
-enum BackgroundSyncEventLastChance {
-  IS_NOT_LAST_CHANCE,
-  IS_LAST_CHANCE
-};
-
-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 {
-  Sync(string tag, BackgroundSyncEventLastChance last_chance)
-      => (ServiceWorkerEventStatus status);
-};
-