chromium/third_party/blink/web_tests/paint/invalidation/background/background-generated.html

<!DOCTYPE HTML>
<head>
    <script src="../resources/text-based-repaint.js" type="text/javascript"></script>
    <script type="text/javascript">
        function repaintTest()
        {
            document.getElementById("target").style.height = "200px";
        }
    </script>
</head>
<body onload="runRepaintAndPixelTest();">
    <div style="width: 100px;
                padding-top: 100px;
                background-image: linear-gradient(red, blue);
    ">
        <div id="target" style="height: 100px;"></div>
    </div>
</body>