In AngularFire you were able to access the providers (e.g Google) accessToken for the authenticated user.
There does not seem to be a way to access this with AngularFire
Getting the auth token from storage in angularfire2
JSON.parse(JSON.stringify(this.afAuth.auth.currentUser)).stsTokenManager.accessToken
As seen in this discussion: https://github.com/angular/angularfire2/issues/725