<!DOCTYPE html>
<body>
  <script>
    var obs = new MutationObserver(function() {
      // Just need something here to assert exception is not pending.  Any
      // binding method will do.
      console.log("hello");
    });
    obs.observe(document.body, { childList: true });
  </script>
  <script>
    noSuchMethodYo();
  </script>
</body>
