Google signin using flirebase in flutter

googlesignin.dart

 Future<User> signInWithGoogle() async {
    final googleSignIn = GoogleSignIn();
    final googleAccount = await googleSignIn.signIn();
    if (googleAccount != null) {
      final googleAuth = await googleAccount.authentication;
      if (googleAuth.accessToken != null && googleAuth.idToken != null) {
        final authResult = await _firebaseAuth.signInWithCredential(
          GoogleAuthProvider.getCredential(
            idToken: googleAuth.idToken,
            accessToken: googleAuth.accessToken,
          ),
        );
        return _userFromFirebase(authResult.user);
      } else {
        throw PlatformException(
          code: 'ERROR_MISSING_GOOGLE_AUTH_TOKEN',
          message: 'Missing Google Auth Token',
        );
      }
    } else {
      throw PlatformException(
        code: 'ERROR_ABORTED_BY_USER',
        message: 'Sign in aborted by user',
      );
    }
  }