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
Future<UserCredential> getRedirectResult() async {
return UserCredential._(this, await _delegate.getRedirectResult());
}