Adapter that bridges between a ProviderSignInController and a application-specific user sign-in service.
Invoked at the end of a provider sign-in attempt to sign-in the local user account associated with the provider user account.
Complete a provider sign-in attempt by signing in the local user account with the specified id.
userId - the local user id
connection - the connection
request - a reference to the current web request; is a "native" web request instance providing access to the native
request and response objects, such as a HttpServletRequest and HttpServletResponse, if needed
the URL that ProviderSignInController should redirect to after sign in. May be null, indicating that ProviderSignInController
should redirect to its postSignInUrl.