<!DOCTYPE html>

<html>
<head>
  <style type="text/css" media="screen">
    iframe {
        border: 10px solid black;
        padding: 5px;
        margin: 20px;
        height: 150px;
        width: 300px;
        -webkit-box-shadow: 0 0 20px black;
        transform: translateZ(0);
    }
    
  </style>
  <script type="text/javascript" charset="utf-8">
    function doTest()
    {
      document.getElementById('iframe').className = 'dummy';
    }
    
    window.addEventListener('load', doTest, false);
  </script>
</head>
<body>

    <iframe id="iframe" src="resources/composited-subframe.html"></iframe>
    
    <p><a href="https://bugs.webkit.org/show_bug.cgi?id=42046">https://bugs.webkit.org/show_bug.cgi?id=42046</a><br>
      You should see a blue rectangle inside the iframe when the page loads.</p>
</body>
</html>