chromium/third_party/blink/web_tests/external/wpt/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/resources/bailout-order-custom-element-with-domain-frame.sub.html

<p>Text</p>
<script>
document.domain = "{{host}}";

class CustomElement extends HTMLElement {
  constructor() {
    super();
    parent.onCustomElementReady();
  }
}
customElements.define("custom-element", CustomElement);
</script>
<custom-element></custom-element>