chromium/third_party/blink/web_tests/svg/custom/textPath-modify-child.svg

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" onload="runTest()">
  <path id="thePath" d="M50 50 L 450 50" />
  <text>
    <textPath id="theTP" xlink:href="#thePath">FAIL</textPath>
  </text>
  <script><![CDATA[
    function runTest() {
      var tp = document.getElementById("theTP");
      tp.firstChild.textContent = "PASS";
    }
  ]]></script>
</svg>