chromium/third_party/blink/web_tests/external/wpt/css/cssom/CSSStyleSheet-constructable-insertRule-base-uri.html

<!doctype html>
<meta charset="utf-8">
<title>CSSStyleSheet.insertRule() on a constructable stylesheet uses the right base uri, even if replace/Sync() hasn't been called yet</title>
<link rel="author" href="https://mozilla.org" title="Mozilla">
<link rel="author" href="mailto:[email protected]" title="Emilio Cobos Álvarez">
<link rel="help" href="https://drafts.csswg.org/cssom/">
<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1880718">
<link rel="match" href="CSSStyleSheet-constructable-insertRule-base-uri-ref.html">
<script>
  const sheet = new CSSStyleSheet();
  sheet.insertRule(`
    :root {
      background-image: url("../../images/green.png");
    }
  `);
  document.adoptedStyleSheets.push(sheet);
</script>