Is the facebook WebView mobile app login app or native login user interface?

I am implementing my own mobile app and I have an identity server that I use to provide public identity for the identity.

I have searched online for a way to authenticate users in my mobile app through its own UI, but according to https://vimeo.com/171942749 , the resource owner of the stream is not recommended and the safer path still remains open and goes through browser redirection.

So I was wondering if this also applies to the facebook app, the login interface we see in the facebook app, the web login page loaded inside a custom web browser or native user interface?