<!DOCTYPE html>
<html>

<head>
    <style type="text/css" media="screen">
        body {
            margin: 0;
            height: 2200px;
        }

        .box {
          height: 100px;
          width: 100px;
        }

        .outer {
            position: fixed;
            top: 0px;
            z-index: 1; /* makes this a stacking context */
            background: blue;
        }

        .inner {
            position: fixed;
            top: 120px;
            left: 120px;
            background: green;
        }
    </style>
    <script type="text/javascript" charset="utf-8">
      if (window.testRunner) {
        testRunner.waitUntilDone();
        testRunner.dumpAsText();
      }

      function doScroll()
      {
        window.setTimeout(function() {
          window.scrollTo(0, 200);
          if (window.testRunner) {
            document.getElementById('results').innerText = window.internals.scrollingStateTreeAsText(document);
            testRunner.notifyDone();
          }
        }, 10);
      }
      
      window.addEventListener('load', doScroll, false);
    </script>
</head>
<body>
    <pre id="results"></pre>
    <div class="outer box">
        <div class="inner box"></div>
    </div>
</body>
</html>