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

third_party/WebKit/Source/modules/mediastream/RTCPeerConnection.idl

 /*
  * Copyright (C) 2012 Google 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
@@ skipping 49 matching lines @@
 // TODO(guidou): Many types are of the wrong type in this interface:
 //  * Dictionary -> specific dictionary types like RTCConfiguration
 //  * VoidCallback -> VoidFunction
 [
     ActiveScriptWrappable,
     DependentLifetime,
     // TODO(guidou): There should only be one constructor argument, and it
     // should be optional.
     Constructor(Dictionary rtcConfiguration, optional Dictionary mediaConstraints),
     ConstructorCallWith=ExecutionContext,
-    GarbageCollected,
     NoInterfaceObject,
     RaisesException=Constructor,
 ] interface RTCPeerConnection : EventTarget {
     [CallWith=ScriptState] Promise<RTCSessionDescription> createOffer(optional RTCOfferOptions options);
     [CallWith=ScriptState] Promise<RTCSessionDescription> createAnswer(optional RTCAnswerOptions options);
     [CallWith=ScriptState] Promise<void> setLocalDescription(RTCSessionDescriptionInit description);
     readonly attribute RTCSessionDescription? localDescription;
     // readonly attribute RTCSessionDescription? currentLocalDescription;
     // readonly attribute RTCSessionDescription? pendingLocalDescription;
     [CallWith=ScriptState] Promise<void> setRemoteDescription(RTCSessionDescriptionInit description);
@@ skipping 43 matching lines @@
     [CallWith=ExecutionContext, RaisesException] void addStream(MediaStream? stream, optional Dictionary mediaConstraints);
     [RaisesException] void removeStream(MediaStream? stream);
     [RaisesException] RTCDTMFSender createDTMFSender(MediaStreamTrack track);
     attribute EventHandler onaddstream;
     attribute EventHandler onremovestream;
 
     // Certificate management
     // http://w3c.github.io/webrtc-pc/#sec.cert-mgmt
     [RaisesException, CallWith=ScriptState] static Promise<RTCCertificate> generateCertificate(AlgorithmIdentifier keygenAlgorithm);
 };