Codebase Browser
chromium
Go to App

chromium/third_party/blink/web_tests/fast/forms/text/input-tab-shows-caret.html 

<!DOCTYPE html>
<html>
<body>
<input>
<script type="text/javascript">
if (window.eventSender)
    eventSender.keyDown("\t");
</script>
</body>
</html>