[material_ui] Migrate M3 ExpansionTile template to use new gen_defaults

packages/material_ui/lib/src/expansion_tile.dart

@@ -23,6 +23,8 @@ import 'material_localizations.dart';
 import 'theme.dart';
 import 'theme_data.dart';
 
+part 'generated/expansion_tile_defaults_m3.g.dart';
+
 const Duration _kExpand = Duration(milliseconds: 200);
 
 /// Enables control over a single [ExpansionTile]'s expanded/collapsed state.
@@ -919,34 +921,3 @@ class _ExpansionTileDefaultsM2 extends ExpansionTileThemeData {
   @override
   Color? get collapsedIconColor => _theme.unselectedWidgetColor;
 }
-
-// BEGIN GENERATED TOKEN PROPERTIES - ExpansionTile
-
-// Do not edit by hand. The code between the "BEGIN GENERATED" and
-// "END GENERATED" comments are generated from data in the Material
-// Design token database by the script:
-//   dev/tools/gen_defaults/bin/gen_defaults.dart.
-
-// dart format off
-class _ExpansionTileDefaultsM3 extends ExpansionTileThemeData {
-  _ExpansionTileDefaultsM3(this.context);
-
-  final BuildContext context;
-  late final ThemeData _theme = Theme.of(context);
-  late final ColorScheme _colors = _theme.colorScheme;
-
-  @override
-  Color? get textColor => _colors.onSurface;
-
-  @override
-  Color? get iconColor => _colors.primary;
-
-  @override
-  Color? get collapsedTextColor => _colors.onSurface;
-
-  @override
-  Color? get collapsedIconColor => _colors.onSurfaceVariant;
-}
-// dart format on
-
-// END GENERATED TOKEN PROPERTIES - ExpansionTile

packages/material_ui/tool/gen_defaults/temporarily_excluded/generated/expansion_tile_defaults.g.dart → packages/material_ui/lib/src/generated/expansion_tile_defaults_m3.g.dart

@@ -2,6 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// Do not edit by hand. The code is generated from data in the Material
+// Design token database by the script:
+//   packages/material_ui/tool/gen_defaults/bin/gen_defaults.dart.
+part of '../expansion_tile.dart';
+
 class _ExpansionTileDefaultsM3 extends ExpansionTileThemeData {
   _ExpansionTileDefaultsM3(this.context);
 

packages/material_ui/tool/gen_defaults/bin/gen_defaults.dart

@@ -28,7 +28,7 @@ import '../templates/card_template.dart';
 // import '../templates/dialog_template.dart';
 // import '../templates/divider_template.dart';
 // import '../templates/drawer_template.dart';
-// import '../templates/expansion_tile_template.dart';
+import '../templates/expansion_tile_template.dart';
 // import '../templates/fab_template.dart';
 // import '../templates/filter_chip_template.dart';
 // import '../templates/icon_button_template.dart';
@@ -85,7 +85,7 @@ Future<void> main(List<String> args) async {
   // const DialogTemplateM3().generateFile(verbose: verbose);
   // const DividerTemplateM3().generateFile(verbose: verbose);
   // const DrawerTemplateM3().generateFile(verbose: verbose);
-  // const ExpansionTileTemplateM3().generateFile(verbose: verbose);
+  const ExpansionTileTemplateM3().generateFile(verbose: verbose);
   // const FabTemplateM3().generateFile(verbose: verbose);
   // const FilterChipTemplateM3().generateFile(verbose: verbose);
   // const IconButtonTemplateM3().generateFile(verbose: verbose);

packages/material_ui/tool/gen_defaults/templates/expansion_tile_template.dart

@@ -0,0 +1,41 @@
+// Copyright 2013 The Flutter Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import '../data/color_role.dart';
+import '../data/list.dart';
+import 'template.dart';
+
+class ExpansionTileTemplateM3 extends TokenTemplateM3 {
+  const ExpansionTileTemplateM3();
+
+  @override
+  String get name => 'Expansion Tile';
+
+  @override
+  String get parentFilePath => 'expansion_tile.dart';
+
+  @override
+  String generateContents(String className) =>
+      '''
+class $className extends ExpansionTileThemeData {
+  $className(this.context);
+
+  final BuildContext context;
+  late final ThemeData _theme = Theme.of(context);
+  late final ColorScheme _colors = _theme.colorScheme;
+
+  @override
+  Color? get textColor => ${color(TokenList.listItemLabelTextColor)};
+
+  @override
+  Color? get iconColor => ${color(TokenColorRole.primary)};
+
+  @override
+  Color? get collapsedTextColor => ${color(TokenList.listItemLabelTextColor)};
+
+  @override
+  Color? get collapsedIconColor => ${color(TokenList.listItemTrailingIconColor)};
+}
+''';
+}

packages/material_ui/tool/gen_defaults/test/gen_defaults_test.dart

@@ -24,7 +24,7 @@ import '../templates/card_template.dart';
 // import '../templates/dialog_template.dart';
 // import '../templates/divider_template.dart';
 // import '../templates/drawer_template.dart';
-// import '../templates/expansion_tile_template.dart';
+import '../templates/expansion_tile_template.dart';
 // import '../templates/fab_template.dart';
 // import '../templates/filter_chip_template.dart';
 // import '../templates/icon_button_template.dart';
@@ -504,8 +504,11 @@ void main() {
     });
 
     test('ExpansionTileTemplateM3 emits M3 ExpansionTile defaults from tokens', () {
-      // Intentionally empty, will be implemented during migration. See:
-      // https://github.com/flutter/flutter/issues/187899
+      final String contents = _generateContents(const ExpansionTileTemplateM3());
+      expect(contents, contains('class _ExpansionTileDefaultsM3 extends ExpansionTileThemeData'));
+      expect(contents, contains('Color? get textColor => _colors.onSurface'));
+      expect(contents, contains('Color? get iconColor => _colors.primary'));
+      expect(contents, contains('Color? get collapsedIconColor => _colors.onSurfaceVariant'));
     });
 
     test('FabTemplateM3 emits M3 Fab defaults from tokens', () {