chromium/third_party/blink/web_tests/external/wpt/css/css-contain/contain-layout-baseline-002.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Containment Test: Layout containment supress baseline in flex items</title>
<link rel="author" title="Manuel Rego Casasnovas" href="mailto:[email protected]">
<link rel="help" href="https://drafts.csswg.org/css-contain-1/#containment-layout">
<link rel="help" href="https://drafts.csswg.org/css-flexbox-1/#valdef-align-items-baseline">
<link rel="match" href="../reference/ref-filled-green-100px-square.xht">
<meta name=assert content="Flex items with layout containment are treated as having no baseline, for that reason their baseline is synthesized from the flex item's border box when they're baseline aligned.">
<style>
#flex {
  display: inline-flex;
  align-items: baseline;
  background: red;
}

canvas {
  background: green;
  width: 50px;
  height: 100px;
}

#item {
  contain: layout;
  color: transparent;
  background: green;
  width: 50px;
  height: 100px;
}
</style>
<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
<div id="flex">
  <canvas></canvas>
  <div id="item">item</div>
</div>