chromium/src/third_party/blink/web_tests/fast/forms/password/password-mismatched_glyph.html

<input type="password" id="passwd">

<script>
    // The verifies the reveal button shows the correct glyph in certain scenario.
    var passwd = document.getElementById("passwd");
    passwd.focus();
    eventSender.keyDown('a'); // The reveal button shows
    eventSender.keyDown('F8', ['altKey']); // The password is revealed.
    passwd.blur(); // passwd hides the reveal-password button AND the password.
    passwd.focus();
    eventSender.keyDown('Backspace'); // Delete 'a' to make the input empty.
    eventSender.keyDown('a'); // The reveal button shows again with correct glyph.
</script>