chromium/third_party/blink/web_tests/fast/hidpi/image-set-content-expected.html

<!DOCTYPE html>
<script src="resources/srcset-helper.js"></script>
<style>
  #foo {
    content: url('resources/green-400-px-square.png');
    width: 200px;
    height: 200px;
  }
</style>

<div>
  This test passes if the divs below are
  100px blue squares when the deviceScaleFactor is 1,
  and 100px green squares when the deviceScaleFactor is 2.
</div>
<br>
<div id="foo"></div>
<br>
<div id="foo"></div>