<!DOCTYPE html>
<html>
<head>
  <style>
    .scroller {
      width: 300px;
      height: 300px;
      overflow: overlay;
      -webkit-overflow-scrolling: touch;
    }

    .column {
      width: 100px;
      height: 100px;
      background: silver;
    }
  </style>
  <script>
    if (window.testRunner)
      testRunner.dumpAsText();

    window.addEventListener('load', function() {
      if (window.testRunner)
        document.getElementById('layers').innerHTML = window.internals.layerTreeAsText(document);
    }, true);
  </script>
</head>

<body>
  <div class="scroller">
    <div class="column">
    </div>
  </div>
  <pre id="layers">Layer tree goes here in DRT</pre>
</body>
</html>