incumbent-document-domain.sub.html | Explore in Territory

<!DOCTYPE html>
<meta charset="utf-8">
<title>Incumbent page used as a test helper</title>

<h1>Incumbent</h1>

<script>
"use strict";
document.domain = "{{hosts[][]}}";

window.createBroadcastChannel = (...args) => {
  return new parent.frames[1].BroadcastChannel(...args);
};
</script>

chromium/third_party/blink/web_tests/external/wpt/webmessaging/multi-globals/support/incumbent-document-domain.sub.html