Partial implementation of subscription restrictions.

third_party/WebKit/Source/modules/push_messaging/PushManager.idl

 // 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.
 
 // https://w3c.github.io/push-api/#pushmanager-interface
 
 [
     Exposed=(Window,ServiceWorker),
     GarbageCollected,
     RuntimeEnabled=PushMessaging,
 ] interface PushManager {
-    [CallWith=ScriptState] Promise<PushSubscription> subscribe(optional PushSubscriptionOptions options);
+    [CallWith=ScriptState, RaisesException] Promise<PushSubscription> subscribe(optional PushSubscriptionOptions options);
     [CallWith=ScriptState] Promise<PushSubscription?> getSubscription();
-    [CallWith=ScriptState] Promise permissionState(optional PushSubscriptionOptions options);
+    [CallWith=ScriptState, RaisesException] Promise permissionState(optional PushSubscriptionOptions options);
 };