chromium/chrome/test/data/password/form_with_only_password_field.html

<html>
  <body>
    <div id="contains-form">
      <form action="done.html">
        <!-- Please note that username input field is
             intentionally excluded here from this form
             (http://crbug.com/406343). -->
        <label for="password">Password</label>
        <input type="password" id="password" name="password"/>
        <input type="submit" id="submit-button" value="Click!"/>
      </form>
    </div>
  </body>
</html>