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

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

 /*
  * Copyright (C) 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
@@ skipping 15 matching lines @@
 
 // An old version of CSSOM View Module defines the ClientRect interface:
 // http://www.w3.org/TR/2011/WD-cssom-view-20110804/#the-clientrect-interface
 
 // It has since been replaced by DOMRect in CSSOM View Module and
 // Geometry Interfaces Module:
 // http://dev.w3.org/csswg/cssom-view/#extension-to-the-element-interface
 // http://dev.w3.org/fxtf/geometry/#DOMRect
 
 [
-    GarbageCollected,
 ] interface ClientRect {
     readonly attribute float top;
     readonly attribute float right;
     readonly attribute float bottom;
     readonly attribute float left;
     readonly attribute float width;
     readonly attribute float height;
 };