[gsi_interface] Introduces canAccessScopes and userDataEvents.

packages/google_sign_in/google_sign_in_platform_interface/CHANGELOG.md

@@ -1,5 +1,8 @@
-## NEXT
+## 2.4.0
 
+* Introduces: `canAccessScopes` method and `userDataEvents` stream.
+  * These enable separation of Authentication and Authorization, and asynchronous
+    sign-in operations where needed (on the web, for example!)
 * Updates minimum Flutter version to 3.3.
 * Aligns Dart and Flutter SDK constraints.
 

packages/google_sign_in/google_sign_in_platform_interface/lib/google_sign_in_platform_interface.dart

@@ -137,6 +137,24 @@ abstract class GoogleSignInPlatform extends PlatformInterface {
   /// Scopes should come from the full  list
   /// [here](https://developers.google.com/identity/protocols/googlescopes).
   Future<bool> requestScopes(List<String> scopes) async {
-    throw UnimplementedError('requestScopes() has not been implmented.');
+    throw UnimplementedError('requestScopes() has not been implemented.');
   }
+
+  /// Determines if the current user can access all [scopes].
+  ///
+  /// Optionally, an [accessToken] can be passed for applications where a
+  /// long-lived token may be cached (like the web).
+  Future<bool> canAccessScopes(
+    List<String> scopes, {
+    String? accessToken,
+  }) async {
+    throw UnimplementedError('canAccessScopes() has not been implemented.');
+  }
+
+  /// Returns a stream of [GoogleSignInUserData] authentication events.
+  ///
+  /// These will normally come from asynchronous flows, like the Google Sign-In
+  /// Button Widget from the Web implementation, and will be funneled directly
+  /// to the `onCurrentUserChanged` Stream of the plugin.
+  Stream<GoogleSignInUserData?>? get userDataEvents => null;
 }

packages/google_sign_in/google_sign_in_platform_interface/pubspec.yaml

@@ -4,7 +4,7 @@ repository: https://github.com/flutter/packages/tree/main/packages/google_sign_i
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+google_sign_in%22
 # NOTE: We strongly prefer non-breaking changes, even at the expense of a
 # less-clean API. See https://flutter.dev/go/platform-interface-breaking-changes
-version: 2.3.1
+version: 2.4.0
 
 environment:
   sdk: ">=2.18.0 <4.0.0"

packages/google_sign_in/google_sign_in_platform_interface/test/method_channel_google_sign_in_test.dart

@@ -141,6 +141,17 @@ void main() {
       expect(log, tests.values);
     });
 
+    test('canAccessScopes is unimplemented', () async {
+      expect(() async {
+        await googleSignIn
+            .canAccessScopes(<String>['someScope'], accessToken: 'token');
+      }, throwsUnimplementedError);
+    });
+
+    test('userDataEvents returns null', () async {
+      expect(googleSignIn.userDataEvents, isNull);
+    });
+
     test('initWithParams passes through arguments to the channel', () async {
       await googleSignIn.initWithParams(const SignInInitParameters(
           hostedDomain: 'example.com',