chromium/third_party/blink/web_tests/editing/selection/editable-links.html

<script>
if (window.testRunner) {
  testRunner.dumpEditingCallbacks();
  testRunner.dumpAsLayoutWithPixelResults();
}
</script>
<body>
<script>
document.designMode = "on";
// Write out the link instead of putting it in the source.  The changes necessary to make links accept a caret aren't made until a layout happens.  This is a bug.
document.write("This is an <a id='link' href='http://www.google.com/'>editable link</a>.");

if (window.testRunner) {
    var link = document.getElementById("link");
    var x = link.offsetLeft + link.offsetParent.offsetLeft + link.offsetWidth / 2;
    var y = link.offsetTop + link.offsetParent.offsetTop + link.offsetHeight / 2;
    
    
    
    eventSender.mouseMoveTo(x, y);
    eventSender.mouseDown();
    eventSender.mouseUp();
}
</script>
</body>