flipped-block-with-local-background.html

<!DOCTYPE html>
<style>
::-webkit-scrollbar {
    display: none;
}

#scroller {
    position: relative;
    z-index: 0;
    width: 100px;
    height: 100px;
    overflow: scroll;
    writing-mode: vertical-rl;
    background: green;
}
</style>
<div id="scroller">
  <div style="width:200px"></div>
</div>
<script>
    document.getElementById('scroller').scrollLeft = -100;
</script>

chromium/third_party/blink/web_tests/fast/writing-mode/flipped-block-with-local-background.html