[google_sign_in/google_identity_services] Clear-up documentation of callbacks in various APIs and uses of those APIs (#8029)

These APIs used to accept allowInterop'd callbacks. When the
implementation was migrated to use dart:js_interop, they were wrapped
with toJS. However, starting in 3.5, to be consistent with dart2wasm,
double-wrapping a function is an error. The documentation should be
clear that it accepts only Dart functions and uses should be cleaned up
to not use allowInterop and type the callbacks' parameter and return
value correctly.
diff --git a/packages/google_identity_services_web/CHANGELOG.md b/packages/google_identity_services_web/CHANGELOG.md
index c9d0ddf..8f47609 100644
--- a/packages/google_identity_services_web/CHANGELOG.md
+++ b/packages/google_identity_services_web/CHANGELOG.md
@@ -1,6 +1,9 @@
-## NEXT
+## 0.3.1+5
 
 * Updates minimum supported SDK version to Flutter 3.22/Dart 3.4.
+* Cleans up documentation of callbacks in `CodeClientConfig`,
+  `TokenClientConfig`, `onGoogleLibraryLoad`, and `revoke` to indicate they only
+  accept Dart functions and not JS functions.
 
 ## 0.3.1+4
 
diff --git a/packages/google_identity_services_web/example/integration_test/js_interop_oauth_test.dart b/packages/google_identity_services_web/example/integration_test/js_interop_oauth_test.dart
index c197b11..cf243b0 100644
--- a/packages/google_identity_services_web/example/integration_test/js_interop_oauth_test.dart
+++ b/packages/google_identity_services_web/example/integration_test/js_interop_oauth_test.dart
@@ -26,7 +26,7 @@
     testWidgets('TokenClientConfig', (_) async {
       final TokenClientConfig config = TokenClientConfig(
         client_id: 'testing_1-2-3',
-        callback: (_) {},
+        callback: (TokenResponse _) {},
         scope: <String>['one', 'two', 'three'],
         include_granted_scopes: true,
         prompt: 'some-prompt',
@@ -34,7 +34,7 @@
         login_hint: 'login-hint@example.com',
         hd: 'hd_value',
         state: 'some-state',
-        error_callback: (_) {},
+        error_callback: (GoogleIdentityServicesError? _) {},
       );
 
       final utils.ExpectConfigValueFn expectConfigValue =
@@ -79,14 +79,14 @@
         scope: <String>['one', 'two', 'three'],
         include_granted_scopes: true,
         redirect_uri: Uri.parse('https://www.example.com/login'),
-        callback: (_) {},
+        callback: (CodeResponse _) {},
         state: 'some-state',
         enable_granular_consent: true,
         login_hint: 'login-hint@example.com',
         hd: 'hd_value',
         ux_mode: UxMode.popup,
         select_account: true,
-        error_callback: (_) {},
+        error_callback: (GoogleIdentityServicesError? _) {},
       );
 
       final utils.ExpectConfigValueFn expectConfigValue =
@@ -110,7 +110,7 @@
     testWidgets('returns a tokenClient', (_) async {
       final TokenClient client = oauth2.initTokenClient(TokenClientConfig(
         client_id: 'for-tests',
-        callback: (_) {},
+        callback: (TokenResponse _) {},
         scope: <String>['some_scope', 'for_tests', 'not_real'],
       ));
 
diff --git a/packages/google_identity_services_web/lib/src/js_interop/google_accounts_id.dart b/packages/google_identity_services_web/lib/src/js_interop/google_accounts_id.dart
index 8467854..99bc706 100644
--- a/packages/google_identity_services_web/lib/src/js_interop/google_accounts_id.dart
+++ b/packages/google_identity_services_web/lib/src/js_interop/google_accounts_id.dart
@@ -164,7 +164,8 @@
   /// ID is the `sub` property of the [CredentialResponse.credential] payload.
   ///
   /// The optional [callback] is a function that gets called to report on the
-  /// success of the revocation call.
+  /// success of the revocation call. It must be a Dart function and not a JS
+  /// function.
   ///
   /// Method: google.accounts.id.revoke
   /// https://developers.google.com/identity/gsi/web/reference/js-reference#google.accounts.id.revoke
diff --git a/packages/google_identity_services_web/lib/src/js_interop/google_accounts_oauth2.dart b/packages/google_identity_services_web/lib/src/js_interop/google_accounts_oauth2.dart
index 9c97ba4..30a843b 100644
--- a/packages/google_identity_services_web/lib/src/js_interop/google_accounts_oauth2.dart
+++ b/packages/google_identity_services_web/lib/src/js_interop/google_accounts_oauth2.dart
@@ -73,7 +73,7 @@
   /// A valid [accessToken] is required to revoke permissions.
   ///
   /// The [done] callback is called once the revoke action is done. It must be
-  /// manually wrapped in [allowInterop] before being passed to this method.
+  /// a Dart function and not a JS function.
   ///
   /// Method: google.accounts.oauth2.revoke
   /// https://developers.google.com/identity/oauth2/web/reference/js-reference#google.accounts.oauth2.revoke
@@ -103,8 +103,7 @@
 abstract class CodeClientConfig {
   /// Constructs a CodeClientConfig object in JavaScript.
   ///
-  /// The [callback] property must be wrapped in [allowInterop] before it's
-  /// passed to this constructor.
+  /// The [callback] property must be a Dart function and not a JS function.
   factory CodeClientConfig({
     required String client_id,
     required List<String> scope,
@@ -230,8 +229,7 @@
 abstract class TokenClientConfig {
   /// Constructs a TokenClientConfig object in JavaScript.
   ///
-  /// The [callback] property must be wrapped in [allowInterop] before it's
-  /// passed to this constructor.
+  /// The [callback] property must be a Dart function and not a JS function.
   factory TokenClientConfig({
     required String client_id,
     required TokenClientCallbackFn callback,
@@ -315,9 +313,6 @@
 @staticInterop
 abstract class OverridableTokenClientConfig {
   /// Constructs an OverridableTokenClientConfig object in JavaScript.
-  ///
-  /// The [callback] property must be wrapped in [allowInterop] before it's
-  /// passed to this constructor.
   factory OverridableTokenClientConfig({
     /// A list of scopes that identify the resources that your application could
     /// access on the user's behalf. These values inform the consent screen that
diff --git a/packages/google_identity_services_web/lib/src/js_interop/load_callback.dart b/packages/google_identity_services_web/lib/src/js_interop/load_callback.dart
index 7df6150..23b0844 100644
--- a/packages/google_identity_services_web/lib/src/js_interop/load_callback.dart
+++ b/packages/google_identity_services_web/lib/src/js_interop/load_callback.dart
@@ -23,8 +23,7 @@
 
 /// Method called after the Sign In With Google JavaScript library is loaded.
 ///
-/// The [callback] parameter must be manually wrapped in [allowInterop]
-/// before being set to the [onGoogleLibraryLoad] property.
+/// The [function] parameter must be a Dart function and not a JS function.
 set onGoogleLibraryLoad(VoidFn function) {
   _onGoogleLibraryLoad = function.toJS;
 }
diff --git a/packages/google_identity_services_web/pubspec.yaml b/packages/google_identity_services_web/pubspec.yaml
index e2b7956..21f6a0c 100644
--- a/packages/google_identity_services_web/pubspec.yaml
+++ b/packages/google_identity_services_web/pubspec.yaml
@@ -2,7 +2,7 @@
 description: A Dart JS-interop layer for Google Identity Services. Google's new sign-in SDK for Web that supports multiple types of credentials.
 repository: https://github.com/flutter/packages/tree/main/packages/google_identity_services_web
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+google_identiy_services_web%22
-version: 0.3.1+4
+version: 0.3.1+5
 
 environment:
   sdk: ^3.4.0
diff --git a/packages/google_sign_in/google_sign_in_web/CHANGELOG.md b/packages/google_sign_in/google_sign_in_web/CHANGELOG.md
index 81e264d..7c3db8f 100644
--- a/packages/google_sign_in/google_sign_in_web/CHANGELOG.md
+++ b/packages/google_sign_in/google_sign_in_web/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.12.4+3
+
+* Fixes callback types for `TokenClientConfig`.
+
 ## 0.12.4+2
 
 * Adds support for `web: ^1.0.0`.
diff --git a/packages/google_sign_in/google_sign_in_web/lib/src/gis_client.dart b/packages/google_sign_in/google_sign_in_web/lib/src/gis_client.dart
index b28796b..421ce1a 100644
--- a/packages/google_sign_in/google_sign_in_web/lib/src/gis_client.dart
+++ b/packages/google_sign_in/google_sign_in_web/lib/src/gis_client.dart
@@ -188,9 +188,9 @@
   //
   // Token clients have an additional `error_callback` for miscellaneous
   // errors, like "popup couldn't open" or "popup closed by user".
-  void _onTokenError(Object? error) {
+  void _onTokenError(GoogleIdentityServicesError? error) {
     if (error != null) {
-      _tokenResponses.addError((error as GoogleIdentityServicesError).type);
+      _tokenResponses.addError(error.type);
     }
   }
 
@@ -223,9 +223,9 @@
     }
   }
 
-  void _onCodeError(Object? error) {
+  void _onCodeError(GoogleIdentityServicesError? error) {
     if (error != null) {
-      _codeResponses.addError((error as GoogleIdentityServicesError).type);
+      _codeResponses.addError(error.type);
     }
   }
 
diff --git a/packages/google_sign_in/google_sign_in_web/pubspec.yaml b/packages/google_sign_in/google_sign_in_web/pubspec.yaml
index ed441ec..85aa2ba 100644
--- a/packages/google_sign_in/google_sign_in_web/pubspec.yaml
+++ b/packages/google_sign_in/google_sign_in_web/pubspec.yaml
@@ -3,7 +3,7 @@
   for signing in with a Google account on Android, iOS and Web.
 repository: https://github.com/flutter/packages/tree/main/packages/google_sign_in/google_sign_in_web
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+google_sign_in%22
-version: 0.12.4+2
+version: 0.12.4+3
 
 environment:
   sdk: ^3.3.0