<!--
Any copyright is dedicated to the Public Domain.
http://creativecommons.org/publicdomain/zero/1.0/
-->
<!DOCTYPE html>
<script>
// Using a DOM bindings object as a weak map key should not crash when attempting to
// call the preserve wrapper callback.
new Worker("data:text/javascript;charset=UTF-8,(new WeakMap()).set(self, 0);")
</script>