root-background-fixed-attachment-positioning.html

<!DOCTYPE html>
<meta name="fuzzy" content="maxDifference=0-1;totalPixels=0-300">
<style>
html {
    background: url('../../paint/invalidation/resources/grid.png');
    position: absolute;
    left: 12px;
    top: 34px;

    background-attachment: fixed;    
}
</style>
Root background with fixed attachment shouldn't be affected by layout of the root box.

chromium/third_party/blink/web_tests/fast/backgrounds/root-background-fixed-attachment-positioning.html