title: How to get access token with new google sign in with play services 8.3?
body: <p>I'm trying to switch to the new google sign-in introduced in google play services 8.3 because it doesn't require the get accounts permission. However, I'm unable to get the access token after logging in the user. </p>
  
  <p>There is a requestIdToken(String clientServerId) method in GoogleSignInOptions.Builder but when I put the Oauth 2 client Id of the app from google developer console, it doesn't even log in the user. </p>
  
  <p>Am I using the wrong Id for the "client Server Id"? </p>