chromium/third_party/blink/web_tests/fast/forms/text/input-text-drag-down.html

<input type="text" value="This is a bunch of text.">
<p>Tests drag-selecting down. If the test succeeds, the text from the center to the end of the text field should be selected.</p>
<script>
if (window.eventSender) {
    eventSender.mouseMoveTo(50, 15);
    eventSender.mouseDown();
    eventSender.mouseUp();
    eventSender.mouseDown();
    eventSender.mouseMoveTo(50, 40);
    eventSender.mouseUp();
}
</script>