title: Unity/Firebase How to authenticate using Google?
body: <p>I'm trying to implement Firebase Authentication system in my Unity Game Project. Everything is setup properly on the console panel on the website. I've read the docs and can't find a way to login into Google using any api within Firebase within Unity. So I bought Prime31's Play GameServices Plugin for Unity.</p>
  
  <p>Here are my questions:</p>
  
  <ol>
  <li><p>How to authenticate using Google right within Firebase? Do I need to manage the google sign in myself?</p></li>
  <li><p>In the Firebase docs I did find:</p></li>
  </ol>
  
  <p>"After a user successfully signs in, exchange the access token for a Firebase credential, and authenticate with Firebase using the Firebase credential:"</p>
  
  <p><code>Firebase.Auth.Credential credential = Firebase.Auth.GoogleAuthProvider.GetCredential(googleIdToken, googleAccessToken);
  auth.SignInWithCredentialAsync(credential).ContinueWith(task =&gt; {
    //......//
  });</code></p>
  
  <p>How can I get the googleIdToken, googleAccessToken which are being passed as parameters above?</p>
  
  <p>Please help (with code). I really like Firebase and would like to make it work without any third party plugins like PRIME31.</p>