Have bindings layer assume and insist that all interface types are GCed.

third_party/WebKit/Source/modules/notifications/Notification.idl

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2011, 2012 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 27 matching lines @@
 };
 
 // https://notifications.spec.whatwg.org/#api
 
 [
     ActiveScriptWrappable,
     ConstructorCallWith=ExecutionContext,
     Constructor(DOMString title, optional NotificationOptions options),
     DependentLifetime,
     Exposed=(Window,Worker),
-    GarbageCollected,
     MeasureAs=NotificationCreated,
     RaisesException=Constructor,
     RuntimeEnabled=Notifications,
 ] interface Notification : EventTarget {
     [CallWith=ExecutionContext, MeasureAs=NotificationPermission] static readonly attribute NotificationPermission permission;
 
     [CallWith=ScriptState, Exposed=Window, MeasureAs=NotificationPermissionRequested] static Promise<NotificationPermission> requestPermission(optional NotificationPermissionCallback deprecatedCallback);
 
     static readonly attribute unsigned long maxActions;
 
@@ skipping 17 matching lines @@
     readonly attribute boolean requireInteraction;
     [CallWith=ScriptState, SameObject] readonly attribute any data;
 
     // TODO(johnme): Ship once Blink supports FrozenArray (https://crbug.com/515920)
     // and we've implemented the additional Object.freeze described in
     // https://notifications.spec.whatwg.org/#dom-notification-actions
     [RuntimeEnabled=NotificationExperimental] readonly attribute sequence<NotificationAction> actions;
 
     [MeasureAs=NotificationClosed] void close();
 };