title: How to get access token after user is signed in from Gmail in Android?
body: <p>I am following <a href="https://developers.google.com/identity/sign-in/android/backend-auth">Google Sign in for Android</a>. Now I can get the <strong>idToken</strong> but my back end server that I have used earlier is expecting <strong>access Token</strong> as I was using Google+ Login earlier. Now I don't want to alter my server side. But still how can I use Google Sign in and get the access Token in my android app so that I can validate my user to my back end server.</p>
  
  <p>I was using GooglePlay Service 7.5.0 previously and now I am using GooglePlay Service latest 8.3.0.</p>