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

third_party/WebKit/Source/core/loader/appcache/ApplicationCache.idl

 /*
  * Copyright (C) 2008, 2009 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 // https://html.spec.whatwg.org/#application-cache-api
 
 [
     DoNotCheckConstants,
-    GarbageCollected,
     // TODO(philipj): Exposed=(Window,SharedWorker)
 ] interface ApplicationCache : EventTarget {
     // update status
     const unsigned short UNCACHED = 0;
     const unsigned short IDLE = 1;
     const unsigned short CHECKING = 2;
     const unsigned short DOWNLOADING = 3;
     const unsigned short UPDATEREADY = 4;
     const unsigned short OBSOLETE = 5;
     readonly attribute unsigned short status;
 
     // updates
     [RaisesException] void update();
     void abort();
     [RaisesException] void swapCache();
 
     // events
     attribute EventHandler onchecking;
     attribute EventHandler onerror;
     attribute EventHandler onnoupdate;
     attribute EventHandler ondownloading;
     attribute EventHandler onprogress;
     attribute EventHandler onupdateready;
     attribute EventHandler oncached;
     attribute EventHandler onobsolete;
 };