Codebase Browser
chromium
Go to App

chromium/third_party/blink/web_tests/external/wpt/html/editing/dnd/overlay/020.xhtml 

<?xml version="1.0" encoding="utf-8"?>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Setting drag image during drag and drop of block element</title>
<style type="text/css">
div
  {width:100px;
  height:100px;
  background-color:navy;}
span
  {color:green;
  background-color:yellow;}
</style>
<script type="application/ecmascript">
function start(event)
  {event.dataTransfer.effectAllowed = 'copy';
  event.dataTransfer.setDragImage(document.querySelector('span'), 1, 1);}
</script>
</head>
<body>
<div draggable="true" ondragstart="start(event)"/>
<p>Try to drag blue box above. You should see word <span>PASS</span> in feedback overlay.</p>
</body>
</html>