<!DOCTYPE html>

<html>
<head>
  <style>
    body {
      height: 5000px;
      margin: 0;
    }
    .fixed {
        position: fixed;
        left: 100px;
        top: 100px;
        width: 200px;
        height: 100px;
        background-color: green;
    }
    
    .forcer {
        position: absolute;
        top: 3100px;
        left: 100px;
        height: 100px;
        width: 100px;
        background-color: red;
        -webkit-transform: translateZ(0);
    }
    
    .child {
        position: absolute;
        left: -9000px;
        top: -9000px;
        height: 10px;
        width: 10px;
        background-color: red;
    }
  </style>
  <script>
    if (window.testRunner) {
      testRunner.dumpAsText();
      testRunner.waitUntilDone();
    }

    function doTest()
    {
        window.scrollTo(0, 3000);
        // Force layout, which updates the fixed layer bounds.
        document.getElementById('layers').innerText = '';
        if (window.testRunner) {
            document.getElementById('layers').innerText = window.internals.layerTreeAsText(document);
            testRunner.notifyDone();
        }
    }

    window.addEventListener('load', doTest, false);
  </script>
</head>

<body>
  <div class="forcer"></div>

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