<!DOCTYPE html>

<html>
<head>
    <style>
        .container {
            border: 1px solid black;
        }
        .box {
          width: 200px;
          height: 200px;
          background-color: red;
        }
        
        .child {
            background-color: green;
            width: 100%;
            height: 100%;
        }
        
        .composited {
            -webkit-transform: translateZ(0);
        }
        
        #negative {
            position: absolute;
            top: 100px;
            height: 50px;
            width: 50px;
            background-color: orange;
            z-index: 0;
        }
        
        #negative.behind {
            z-index: -1;
        }
    </style>
    <script>
        if (window.testRunner)
            testRunner.waitUntilDone();
        function doTest()
        {
            window.setTimeout(function() {
                document.getElementById('negative').classList.remove('behind');
                if (window.testRunner)
                    testRunner.notifyDone();
            }, 0)
        }
        window.addEventListener('load', doTest, false);
    </script>
</head>
<body>
    <div class="container composited box">
        <div class="child"></div>
        <div id="negative" class="composited behind box"></div>
    </div>
</body>
</html>