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

third_party/WebKit/Source/core/dom/DOMException.idl

 /*
  * Copyright (C) 2007 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
@@ skipping 16 matching lines @@
  */
 
 // Web IDL exceptions are defined in prose rather than IDL.
 // http://heycam.github.io/webidl/#idl-exceptions
 // http://heycam.github.io/webidl/#es-DOMException
 
 [
     Constructor(optional DOMString message = "", optional DOMString name = "Error"),
     Exposed=(Window,Worker),
     DoNotCheckConstants,
-    GarbageCollected,
 ] exception DOMException {
 
     readonly attribute unsigned short   code;
     readonly attribute DOMString        name;
     readonly attribute DOMString        message;
 
     // Override in a Mozilla compatible format
     [NotEnumerable] DOMString toString();
 
     // ExceptionCode
@@ skipping 27 matching lines @@
     const unsigned short      NETWORK_ERR                    = 19;
     const unsigned short      ABORT_ERR                      = 20;
     const unsigned short      URL_MISMATCH_ERR               = 21;
     const unsigned short      QUOTA_EXCEEDED_ERR             = 22;
     // TIMEOUT_ERR is currently unused but was added for completeness.
     const unsigned short      TIMEOUT_ERR                    = 23;
     // INVALID_NODE_TYPE_ERR is currently unused but was added for completeness.
     const unsigned short      INVALID_NODE_TYPE_ERR          = 24;
     const unsigned short      DATA_CLONE_ERR                 = 25;
 };