From the description of the Google add-on currently available it seems that it's mainly for receipt validation.
"Note that you do not need to install this add-on in order to login with a Google account."
So what about simple Google Sign In (Google OAuth 2.0, Google+) and Google Cloud Messaging (Push Notifications)?
Google settings have changed. I came back after finishing mirating my android plugin to the new Google SignIn API to check why I'm getting "InavlidGoogleToken" error from PlayFab and I have found out that instead of application package name(e.g. com.Company.App) and Public Key (secret), what is required now are Google App Package ID and Google App License Key from Google Play.
I want to make sure I'm sending the right token.