chromium/third_party/blink/web_tests/compositing/background-color/background-color-padding-clip.html

<html>
    <head>
        <style type="text/css">
            .green {
                width: 100px;
                height: 100px;
                background-color: green;
                display: block;
                padding: 10px;
                -webkit-background-clip: padding;
            }
            .blue {
                width: 50px;
                height: 50px;
                background-color: blue;
                display: block;
            }

            .composited {
                will-change: transform;
            }
        </style>
    </head>
    <body>
        <div class="green composited">
            <div class="blue composited">
            </div>
        </div>
    </body>
</html>