overflow-scroll-background-transparent-to-opaque-expected.html

<!DOCTYPE html>
<style>
#scroller {
    background: green local content-box;
    border: 10px solid rgba(0, 255, 0, 0.5);
    contain: paint;
    overflow: scroll;
    width: 200px;
    height: 200px;
}
.spacer {
    height: 300px;
}
</style>
<div id="scroller"><div class="spacer"></div></div>
<p>Scroller background should be green</p>

chromium/third_party/blink/web_tests/compositing/overflow/overflow-scroll-background-transparent-to-opaque-expected.html