chromium/third_party/blink/web_tests/external/wpt/svg/render/reftests/render-sync-with-font-size.html

<!doctype html>
<html class="reftest-wait">
<title>Render is synchronized with font-size change</title>
<link rel="match" href="render-sync-with-font-size-ref.html">
<svg width="400" height="400" style="font-size:10px" onload="main()">
  <rect width="5em" height="5em" rx="5px" ry="5px" fill="magenta" />
  <circle cx="10em" cy="5em" r="4em" fill="purple" />
  <line y1="6em" x2="15em" y2="6em" stroke="skyblue" />
</svg>
<script>
  function main() {
    window.requestAnimationFrame(() => {
      let s = document.querySelector("svg");
      s.style.fontSize = "20px";
      window.requestAnimationFrame(() => {
        document.documentElement.removeAttribute("class");
      });
    });
  };
</script>
</html>