<!DOCTYPE html>
<html>
<head>
  <style type="text/css" media="screen">
    #box {
        height: 170px;
        width: 320px;
        float: left;
        margin-top: 55px;
        background-color: silver;
        will-change: transform;
    }
    
    #overlay {
        position: absolute;
        width: 150px;
        height: 50px;
        top: 5px;
        left: 5px;
        background-color: rgba(0, 128, 0, 0.9);
    }
    
    pre {
        clear: both;
    }
  </style>
  <script type="text/javascript" charset="utf-8">
    if (window.testRunner) {
        testRunner.dumpAsText();
        testRunner.waitUntilDone();
    }

    function doTest()
    {
        // Need to wait for compositing layers to be updated.
        window.setTimeout(function() {
          document.getElementById('overlay').style.height = '150px';
            if (window.testRunner) {
                testRunner.displayAndTrackRepaints(); // Painting has to happen to detect overlap.
                document.getElementById('layers').innerHTML = window.internals.layerTreeAsText(document);
                testRunner.notifyDone();
            }
        }, 0);
    }

    window.addEventListener('load', doTest, false);
  </script>
</head>
<body>
    <div id="box"></div>
    <div id="overlay"></div>
    
    <pre id="layers">Layer tree appears here in DRT.</pre>
</body>
</html>