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

third_party/WebKit/Source/core/frame/Location.idl

 /*
  * Copyright (C) 2008 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 13 matching lines @@
  * 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.
  */
 
 // https://html.spec.whatwg.org/#the-location-interface
 
 [
     CheckSecurity=Receiver,
     Unforgeable,
-    GarbageCollected,
 ] interface Location {
     // |assign|, |replace|, and *writing* |href| do not require a security
     // check, as they *change* the page, and thus these do not change any
     // property of an *existing* document at a different origin.
     // However, *reading* |href|, or accessing any component, is a security
     // problem, since that allows tracking navigation.
     [CallWith=(CurrentWindow,EnteredWindow), DoNotCheckSecurity, RaisesException] void assign(DOMString url);
     [CallWith=(CurrentWindow,EnteredWindow), DoNotCheckSecurity, RaisesException] void replace(DOMString url);
     [CallWith=CurrentWindow] void reload();
 
@@ skipping 13 matching lines @@
     [SetterCallWith=(CurrentWindow,EnteredWindow)] attribute DOMString hostname;
     [SetterCallWith=(CurrentWindow,EnteredWindow)] attribute DOMString port;
     [SetterCallWith=(CurrentWindow,EnteredWindow)] attribute DOMString pathname;
     [SetterCallWith=(CurrentWindow,EnteredWindow)] attribute DOMString search;
     [SetterCallWith=(CurrentWindow,EnteredWindow)] attribute DOMString hash;
 
     // TODO(philipj): Location does not have a valueOf() override in the spec.
     // See the comment in Location.h for the purpose of this.
     [NotEnumerable, CallWith=ThisValue] any valueOf();
 };