Revert "Updating the example to match the new API (flutter#1155)"

This reverts commit 5f6eec8.

Author: andreidiaconu

packages/firebase_auth/CHANGELOG.md

@@ -1,7 +1,3 @@
-## 0.8.0+2
-
-* Update Google sign-in example in the README.
-
 ## 0.8.0+1
 
 * Update a broken dependency.

packages/firebase_auth/README.md

@@ -61,15 +61,12 @@ final FirebaseAuth _auth = FirebaseAuth.instance;
 You can now use the Firebase `_auth` to authenticate in your Dart code, e.g.
 ```dart
 Future<FirebaseUser> _handleSignIn() async {
-  final GoogleSignInAccount googleUser = await _googleSignIn.signIn();
-  final GoogleSignInAuthentication googleAuth = await googleUser.authentication;
-
-  final AuthCredential credential = GoogleAuthProvider.getCredential(
+  GoogleSignInAccount googleUser = await _googleSignIn.signIn();
+  GoogleSignInAuthentication googleAuth = await googleUser.authentication;
+  FirebaseUser user = await _auth.signInWithGoogle(
     accessToken: googleAuth.accessToken,
     idToken: googleAuth.idToken,
   );
-  
-  final FirebaseUser user = await _auth.signInWithCredential(credential);
   print("signed in " + user.displayName);
   return user;
 }

packages/firebase_auth/pubspec.yaml

@@ -4,7 +4,7 @@ description: Flutter plugin for Firebase Auth, enabling Android and iOS
   like Google, Facebook and Twitter.
 author: Flutter Team <flutter-dev@googlegroups.com>
 homepage: https://github.com/flutter/plugins/tree/master/packages/firebase_auth
-version: "0.8.0+2"
+version: "0.8.0+1"
 
 flutter:
   plugin: