<!DOCTYPE html>
<html>
<body onload="go()">
  <svg id="outerSvg" width="50%" height="50%"
       style="border: 1px solid black">
  </svg>
  <script type="application/javascript">
    /* I'm not sure what exactly was required to trigger bug 1288228's crash,
     * but it involved tweaking a length's specified units and cycle-collecting
     * and reloading (in some combination).  So, we'll tweak the units and
     * cycle-collect a few times, and message the outer page to reload us
     * after we've made the first tweak.
     */
    const maxTweaks = 5;
    let remainingTweaks = maxTweaks;

    var savedBaseVal =  document.getElementById("outerSvg").width.baseVal;
    function go() {
      window.parent.SpecialPowers.DOMWindowUtils.cycleCollect();
      tweak();
    }

    function tweak() {
      console.log("tweaked");
      savedBaseVal.convertToSpecifiedUnits(SVGLength.SVG_LENGTHTYPE_PX);
      savedBaseVal.convertToSpecifiedUnits(SVGLength.SVG_LENGTHTYPE_PERCENTAGE);
      if (remainingTweaks == maxTweaks) {
        window.parent.postMessage("ping", "*"); // only do this on first tweak
      }
      if (--remainingTweaks) {
        setTimeout(tweak, 0);
      }
    }
</script>
</body>
</html>
