chromium/third_party/blink/web_tests/fast/css/fixed-width-intrinsic-width-excludes-scrollbars.html

<!DOCTYPE html>
<style>
.container {
    display: -webkit-flex;
    display: -moz-flex;
    display: -ie-flex;
    display: -o-flex;
    display: flex;
}
.container > div {
    overflow: scroll;
    width: 50px;
    height: 50px;
}
</style>

<div class="container" style="display: -webkit-flex">
    <div></div>
    <div style="display:-webkit-flex;"></div>
    <div style="display:-webkit-box;"></div>
</div>

<script src="../../resources/check-layout.js"></script>
<script>
Array.prototype.forEach.call(document.querySelectorAll('.container > div'), function(item) {
    item.setAttribute('data-expected-width', 50);
    item.setAttribute('data-expected-height', 50);
});
checkLayout('.container');
</script>