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chromium/third_party/blink/web_tests/fast/multicol/composited-relpos-resize.html 

<!DOCTYPE html>
<p>There should be one yellow box below. There is only one because the content is composited, and hence not fragmented.</p>
<div id="elm" style="-webkit-columns:2; -webkit-column-gap:0; column-fill:auto; height:13em; line-height:2em;">
    <div style="will-change:transform; position:absolute; left:0; right:0; height:15em; background:cyan;"></div>
    <br>
    <br>
    <br>
    <br>
    <div style="position:relative; margin:0.5em; background:yellow;">
        first<br>
        column<br>
        second<br>
        column<br>
    </div>
</div>
<script>
    if (window.internals)
        internals.forceCompositingUpdate(document);
    document.getElementById('elm').style.width = '90%';
</script>