[Background Sync] Allow sync manager access from uncontrolled clients

Source/modules/background_sync/PeriodicSyncManager.idl

 // 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.
 
 [
     Exposed=(Window,ServiceWorker),
     GarbageCollected,
     RuntimeEnabled=BackgroundSyncPeriodic,
     TypeChecking=Interface,
 ] interface PeriodicSyncManager {
-    [CallWith=ScriptState,ImplementedAs=registerFunction] Promise<PeriodicSyncRegistration> register([RuntimeEnabled=BackgroundSyncV2] optional PeriodicSyncRegistrationOptions options);
+    [CallWith=(ScriptState,ExecutionContext),ImplementedAs=registerFunction] Promise<PeriodicSyncRegistration> register([RuntimeEnabled=BackgroundSyncV2] optional PeriodicSyncRegistrationOptions options);
     [CallWith=ScriptState] Promise<PeriodicSyncRegistration> getRegistration(DOMString tag);
     [CallWith=ScriptState] Promise<sequence<PeriodicSyncRegistration>> getRegistrations();
     [RuntimeEnabled=BackgroundSyncV2, CallWith=ScriptState] Promise<SyncPermissionState> permissionState();
     [RuntimeEnabled=BackgroundSyncV2] readonly attribute unsigned long minPossiblePeriod;
 };