getRedirectResult method
Returns a UserCredential from the redirect-based sign-in flow.
If sign-in succeeded, returns the signed in user. If sign-in was
unsuccessful, fails with an error. If no redirect operation was called,
returns a UserCredential
with a null User.
This method is only support on web platforms.
Implementation
@override
Future<UserCredentialPlatform> getRedirectResult() {
// TODO: implement getRedirectResult
throw UnimplementedError();
}