@mkdynamic @simi Sorry for the delay, I changed this method to be `protected` because of this:
https://github.com/intridea/omniauth-oauth2/blob/8a7a97ecbdb71c04b96bfa47dbc465d5d931f694/lib/omniauth/strategies/oauth2.rb#L89

As you can see `OmniAuth::Strategies::OAuth2` defines `#build_access_token` as a `protected` method. 

On the other hand, OmniAuth::Strategies::Facebook changes the visibility of the method. 

Do you guys have a good reason to do that?