Login to my app via Facebook

I am looking through some of the new spring-social work that is being done and noticed that a method was dropped off the ServiceProvider interface from the migration from greenhouse, findAccountByConnection(String accessToken). What this intentional? The reason I ask is that I would like to do what Greenhouse does, signin to my app via facebook, redirect to a registration form with populated info from facebook, and then register and connect the facebook and app account together.

Given the new structure and the use of AccountIdResolver, how could I do such a thing? It seems like everything relies on having some sort of application accountId to look up a connection vs just a the accessToken.

-Matt