title: Sign in user to google account in Windows Service (without browser and user actions)
body: <p>I am trying to get user tokens in windows service. Application know username and password, and each day is creating new events in user calendar. </p>
  
  <p>For now, as workaround, I create another (desktop) app, just to get user tokens when I need it, but this requires action from user, and users are not signin to server every day to check that all processes are working properly.</p>
  
  <p>Is there any way to sign in to google calendar api without this pop up browser and to get user credentials?</p>