Add Material 3 support for `Slider` - Part 1 (#114079)

dev/tools/gen_defaults/bin/gen_defaults.dart

@@ -38,6 +38,7 @@ import 'package:gen_defaults/navigation_rail_template.dart';
 import 'package:gen_defaults/popup_menu_template.dart';
 import 'package:gen_defaults/progress_indicator_template.dart';
 import 'package:gen_defaults/radio_template.dart';
+import 'package:gen_defaults/slider_template.dart';
 import 'package:gen_defaults/surface_tint.dart';
 import 'package:gen_defaults/switch_template.dart';
 import 'package:gen_defaults/text_field_template.dart';
@@ -144,6 +145,7 @@ Future<void> main(List<String> args) async {
   PopupMenuTemplate('PopupMenu', '$materialLib/popup_menu.dart', tokens).updateFile();
   ProgressIndicatorTemplate('ProgressIndicator', '$materialLib/progress_indicator.dart', tokens).updateFile();
   RadioTemplate('Radio<T>', '$materialLib/radio.dart', tokens).updateFile();
+  SliderTemplate('md.comp.slider', 'Slider', '$materialLib/slider.dart', tokens).updateFile();
   SurfaceTintTemplate('SurfaceTint', '$materialLib/elevation_overlay.dart', tokens).updateFile();
   SwitchTemplate('Switch', '$materialLib/switch.dart', tokens).updateFile();
   TextFieldTemplate('TextField', '$materialLib/text_field.dart', tokens).updateFile();

dev/tools/gen_defaults/lib/slider_template.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'template.dart';
+
+class SliderTemplate extends TokenTemplate {
+  const SliderTemplate(this.tokenGroup, super.blockName, super.fileName, super.tokens, {
+    super.colorSchemePrefix = '_colors.',
+  });
+
+  final String tokenGroup;
+
+  @override
+  String generate() => '''
+class _${blockName}DefaultsM3 extends SliderThemeData {
+  _${blockName}DefaultsM3(this.context)
+    : _colors = Theme.of(context).colorScheme,
+      super(trackHeight: ${tokens['$tokenGroup.active.track.height']});
+
+  final BuildContext context;
+  final ColorScheme _colors;
+
+  @override
+  Color? get activeTrackColor => ${componentColor('$tokenGroup.active.track')};
+
+  @override
+  Color? get inactiveTrackColor => ${componentColor('$tokenGroup.inactive.track')};
+
+  @override
+  Color? get secondaryActiveTrackColor => _colors.primary.withOpacity(0.54);
+
+  @override
+  Color? get disabledActiveTrackColor => ${componentColor('$tokenGroup.disabled.active.track')};
+
+  @override
+  Color? get disabledInactiveTrackColor => ${componentColor('$tokenGroup.disabled.inactive.track')};
+
+  @override
+  Color? get disabledSecondaryActiveTrackColor => _colors.onSurface.withOpacity(0.12);
+
+  @override
+  Color? get activeTickMarkColor => ${componentColor('$tokenGroup.with-tick-marks.active.container')};
+
+  @override
+  Color? get inactiveTickMarkColor => ${componentColor('$tokenGroup.with-tick-marks.inactive.container')};
+
+  @override
+  Color? get disabledActiveTickMarkColor => ${componentColor('$tokenGroup.with-tick-marks.disabled.container')};
+
+  @override
+  Color? get disabledInactiveTickMarkColor => ${componentColor('$tokenGroup.with-tick-marks.disabled.container')};
+
+  @override
+  Color? get thumbColor => ${componentColor('$tokenGroup.handle')};
+
+  @override
+  Color? get disabledThumbColor => Color.alphaBlend(${componentColor('$tokenGroup.disabled.handle')}, _colors.surface);
+
+  @override
+  Color? get overlayColor => MaterialStateColor.resolveWith((Set<MaterialState> states) {
+    if (states.contains(MaterialState.hovered)) {
+      return ${componentColor('$tokenGroup.hover.state-layer')};
+    }
+    if (states.contains(MaterialState.focused)) {
+      return ${componentColor('$tokenGroup.focus.state-layer')};
+    }
+    if (states.contains(MaterialState.dragged)) {
+      return ${componentColor('$tokenGroup.pressed.state-layer')};
+    }
+
+    return Colors.transparent;
+  });
+}
+''';
+
+}