<!DOCTYPE html>

<html>
<head>
    <style>
        #container {
            width: 200px;
            height: 200px;
            overflow: hidden;
            border: 1px solid black;
        }
        
        .scroll-content {
            height: 600px;
        }
        
        .inner {
            position: relative;
            width: 150px;
            height: 150px;
            margin-top: -10px; /* force overlap with the composited element */
            margin-left: 10px;
            box-sizing: border-box;
            border: 40px solid black;
        }
        
        .composited {
            height: 150px;
            width: 100px;
            -webkit-transform: translateZ(0);
        }
    </style>
    <script>
        if (window.testRunner)
            testRunner.waitUntilDone();

        function doTest()
        {
            window.setTimeout(function() {
                var container = document.getElementById('container');
                window.console.log('scrolling')
                container.scrollTop = 100;
                if (window.testRunner)
                    testRunner.notifyDone();
            }, 0);
        }
        window.addEventListener('load', doTest, false);
    </script>
</head>
<body>

    <div id="container">
        <div class="scroll-content">
            <div class="composited"></div>
            <div class="inner"></div>
        </div>
    </div>
</body>
</html>