<!DOCTYPE html> <!-- webkit-test-runner [ MockScrollbarsEnabled=false AsyncOverflowScrollingEnabled=true ] -->
<html>
<head>
    <meta name="color-scheme" content="light dark">
    <style>
        body {
            background-color: white;
        }

        .scroller {
            width: 400px;
            height: 450px;
            border: 2px solid black;
            overflow: scroll;
        }

        .contents {
            height: 300%;
        }
    </style>
    <script src="../../../resources/ui-helper.js"></script>
    <script>
        if (window.testRunner)
            testRunner.waitUntilDone();

        if (window.internals) {
            internals.settings.setUseDarkAppearance(true);
            internals.setUsesOverlayScrollbars(true);
        }

        async function runTest()
        {
            if (!testRunner.runUIScript)
                return;

            let scroller = document.querySelector('.scroller');

            // Trigger scrollbar display.
            scroller.scrollTop = 10;
            // Ensure scrollbar is drawn once.
            await UIHelper.ensureStablePresentationUpdate();

            internals.settings.setUseDarkAppearance(false);
            // Trigger scrollbar display.
            scroller.scrollTop = 20;

            testRunner.notifyDone();
        }

        window.addEventListener('load', runTest, false);
    </script>
</head>
<body>
    <div class="scroller">
        <div class="contents">
        </div>
    </div>
</body>
</html>