I am unable to move forward with the Module ''Set up Social Sign-on Unit'' (https://trailhead.salesforce.com/identity/identity_external/identity_external_social) in Trailhead as the challenge is to set up a Google Social Sign-on, however it seems that the Registration Handler provided is for Facebook rather than Google. Is someone able to provide some support /suggestions on this so I can move forward please? 

Registration Handler provided: https://github.com/salesforceidentity/IdentityTrail-Module3 and use Module3RegistrationHandler.cls