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

third_party/WebKit/Source/core/frame/Screen.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 11 matching lines @@
  * (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.
  */
 
 // http://dev.w3.org/csswg/cssom-view/#the-screen-interface
 
 [
-    GarbageCollected,
 ] interface Screen {
     readonly attribute long availWidth;
     readonly attribute long availHeight;
     readonly attribute long width;
     readonly attribute long height;
     readonly attribute unsigned long colorDepth;
     readonly attribute unsigned long pixelDepth;
 
     // Non-standard
     [Measure] readonly attribute long availLeft;
     [Measure] readonly attribute long availTop;
 };