chromium/third_party/blink/web_tests/compositing/plugins/webplugin-reflection.html

<!DOCTYPE html>
<html>
<head>
<style>
  #plugin {
    width: 150px;
    height: 150px;
    -webkit-box-reflect: below 20px;
  }
</style>
</head>

<body>
<!-- You should see a blue triangle on green background and its reflection -->

<embed id="plugin" type="application/x-webkit-test-webplugin" primitive="triangle" background-color="green" primitive-color="blue">
</body>
</html>