Objective C: How to get access token from web browser to cocoa app?

@property (nonatomic) booleanDraw;

@synthesize booleanDraw;

- (GTMOAuth2ViewControllerTouch *)createAuthController {
GTMOAuth2ViewControllerTouch *authController;
// If modifying these scopes, delete your previously saved credentials by
// resetting the iOS simulator or uninstall the app.
NSArray *scopes = [NSArray arrayWithObjects:kGTLAuthScopeGmailReadonly, nil];
authController = [[GTMOAuth2ViewControllerTouch alloc]
                  initWithScope:[scopes componentsJoinedByString:@" "]
                  clientID:kClientID
                  clientSecret:nil
                  keychainItemName:kKeychainItemName
                  delegate:self
                  finishedSelector:@selector(viewController:finishedWithAuth:error:)];
return authController;
}


- (void)viewController:(GTMOAuth2ViewControllerTouch *)viewController
  finishedWithAuth:(GTMOAuth2Authentication *)authResult
             error:(NSError *)error {
if (error != nil) {
   ...
}
else {
    NSLog(@"Access token: %@", authResult.accessToken);

 }
}

- (void)viewDidAppear:(BOOL)animated {
if (!self.service.authorizer.canAuthorize) {
    // Not yet authorized, request authorization by pushing the login UI onto the UI stack.
    [self presentViewController:[self createAuthController] animated:YES completion:nil];
}

NSLog(@"Token: %@ id: %@", [GIDSignIn sharedInstance].currentUser.authentication.accessToken, [GIDSignIn sharedInstance].currentUser.userID);

NSLog(@"Token: %@ id: %@", authResult.accessToken, authResult.userID);