dynamic-preferred-root-scrollbar-color-scheme-change.html

<!DOCTYPE html>
<!-- Verifies root scrollbars are painted dark when both preferred color scheme
     and preferred root scrollbar color scheme are dark. -->
<link rel="match" href="dynamic-preferred-root-scrollbar-color-scheme-change-expected.html">
<script src="../../../../resources/run-after-layout-and-paint.js"></script>

<style>
  :root {
    background-color: green;
    height: 5000px;
    width: 5000px;
  }
</style>

<script>
    runAfterLayoutAndPaint(() => {
      window.internals.setDarkPreferredColorScheme(document);
      window.internals.setDarkPreferredRootScrollbarColorScheme(document);
    }, true);
</script>

chromium/third_party/blink/web_tests/fast/forms/color-scheme/scrollbar/dynamic-preferred-root-scrollbar-color-scheme-change.html