1. The revoke button is not working, it works as Sign out.
2. I find very difficult to create a custom Sign In button with the change on guidelines and the assets i downloaded form the site. Now I cannot follow the steps as you indicate on the video.
I guess the videos are a bit outdated now as things are different now.
(I also posted this questions on Udacity's forum, and I'm also waiting for help there)
Thanks a lot for your help and time.
I wrote a series of blog posts on the new API on the Android Developers blog which should be a good getting started...they also link to the excellent samples. Hope that helps!