Login Authentication using the Chrome browser

Authentication methods / captive portals do not have any native way of filtering for specific browser.

You could potentially try to pre-filter traffic based on the User-Agent Header values, but that's only an explicit-proxy feature, as far as I am aware. It most likely would not work in regular firewall policies.

There are App Control signatures "HTTP.Browser_*" for popular browsers, but since app-based filtering happens only after policy match and authentication, this wouldn't help you with regular firewall policies.