<!DOCTYPE html>

<html>
<head>
    <style>
        body {
            height: 1000px;
        }
        .box {
            position: absolute;
            top: 200px;
            left: 10px;
            width: 100px;
            height: 100px;
            background-image: linear-gradient(green, green 200px, red 200px, red 1000px);
            background-attachment: fixed;
        }
    </style>
    <script>
        if (window.testRunner)
            testRunner.dumpAsText();

        function logRepaints() {
            if (!window.internals)
                return;

            document.getElementById('repaints').textContent = window.internals.repaintRectsAsText();
            window.internals.stopTrackingRepaints();
        }

        function doTest()
        {
            if (window.eventSender)
                eventSender.scalePageBy(2, 0, 0);

            window.internals.startTrackingRepaints();
            window.scrollTo(0, 200);
            logRepaints();
        }
        
        window.addEventListener('load', doTest, false);
    </script>
</head>
<body>
<div class="box"></div>
<div id="repaints"></div>
</body>
</html>