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

third_party/WebKit/Source/modules/websockets/WebSocket.idl

 /*
  * Copyright (C) 2009 Google Inc.  All rights reserved.
  * Copyright (C) 2010, 2011 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 21 matching lines @@
 // https://html.spec.whatwg.org/multipage/comms.html#the-websocket-interface
 
 enum BinaryType { "blob", "arraybuffer" };
 
 [
     ActiveScriptWrappable,
     Constructor(DOMString url, optional (DOMString or sequence<DOMString>) protocols),
     ConstructorCallWith=ExecutionContext,
     DependentLifetime,
     Exposed=(Window,Worker),
-    GarbageCollected,
     ImplementedAs=DOMWebSocket,
     RaisesException=Constructor,
 ] interface WebSocket : EventTarget {
     readonly attribute DOMString url;
 
     // ready state
     const unsigned short CONNECTING = 0;
     const unsigned short OPEN = 1;
     const unsigned short CLOSING = 2;
     const unsigned short CLOSED = 3;
     readonly attribute unsigned short readyState;
     readonly attribute unsigned long bufferedAmount;
 
     // networking
     attribute EventHandler onopen;
     attribute EventHandler onerror;
     attribute EventHandler onclose;
     readonly attribute DOMString extensions;
     readonly attribute DOMString protocol;
     [RaisesException] void close([Clamp] optional unsigned short code, optional USVString reason);
 
     // messaging
     attribute EventHandler onmessage;
     attribute BinaryType binaryType;
     [RaisesException] void send(USVString data);
     [RaisesException] void send(Blob data);
     [RaisesException] void send(ArrayBuffer data);
     [RaisesException] void send(ArrayBufferView data);
 };