chromium/third_party/blink/web_tests/svg/text/adding-id-on-pending-path.html

<!DOCTYPE html>
<svg>
  <path d="M0,20h100" fill="none"/>
  <text><textPath xlink:href="#path">PASS</textPath></text>
</svg>
<script src="../../resources/run-after-layout-and-paint.js"></script>
<script>
runAfterLayoutAndPaint(function() {
  document.querySelector('path').id = 'path';
}, true);
</script>