<!DOCTYPE HTML>
<html reftest-async-scroll class="reftest-wait" style="overflow: hidden;">
<head>
  <script>
  function scroll() {
    document.getElementById("thediv").scrollTop = 400;
    document.documentElement.removeAttribute("class");
  }
  </script>
</head>
<body onload="scroll();" style="overflow: hidden;">
  <div style="background: white; position: absolute; top: 0; left: 0; bottom: 0; right: 0;">
    <div style="background: yellow; height: 10%;"></div>
    <div reftest-displayport-x="0" reftest-displayport-y="-300"
         reftest-displayport-w="800" reftest-displayport-h="2000"
         style="overflow: scroll; height: 90%;"
         id="thediv">
      <div style="background: purple; height: 4000px;"><div style="height: 500px; width: 100px; background: orange;"></div></div>
    </div>
  </div>
</body>
</html>