GoogleSignInApi Api interface for Sign In with Google. 
GoogleSignInOptionsExtension An interface for API specific extension for GoogleSignInOptions


GoogleSignIn Entry point for the Google Sign In API. 
GoogleSignInAccount Class that holds the basic account information of the signed in Google user. 
GoogleSignInClient A client for interacting with the Google Sign In API. 
GoogleSignInOptions GoogleSignInOptions is options used to configure the GOOGLE_SIGN_IN_API
GoogleSignInOptions.Builder Builder for GoogleSignInOptions,  
GoogleSignInResult GoogleSignInResults are Result implementations that potentially contain a GoogleSignInAccount
GoogleSignInStatusCodes Google Sign In specific status codes, for use in Status#getStatusCode()
RevocationBoundService Handles Google Sign-In user revocation.