chromium/third_party/blink/web_tests/fast/sub-pixel/shadows-hidpi.html

<!DOCTYPE html>
<script>
    function startTest() {
        if (window.testRunner) {
            testRunner.waitUntilDone();
            testRunner.setBackingScaleFactor(2, finishTest);
        }
    }

    function finishTest() {
        testRunner.notifyDone();
    }
</script>

<style>
  body {
    font-family: Ahem;
    font-size: 10px;
  }
  #text {
    text-shadow: 0.5px 1.5px 0px red;
  }
  .box {
    box-shadow: 2.5px 30.5px 0px 0px red;
    border: 1px black solid;
    display: inline-block;
  }
  .box2 {
    box-shadow: 2px 30px 0px 0.5px red;
    border: 1px black solid;
    display: inline-block;
  }
</style>

<script src="../../resources/ahem.js"></script>
<body onload="startTest();">

<div id="text">XXX</div>
<br>
<br>
<div class="box">XXX</div>
<div class="box2">XXX</div>

</body>