Add `InheritedTheme` support to `ScrollbarTheme` (#120970)

packages/flutter/lib/src/material/scrollbar_theme.dart

@@ -299,7 +299,7 @@ bool? _lerpBool(bool? a, bool? b, double t) => t < 0.5 ? a : b;
 ///
 ///  * [ScrollbarThemeData], which describes the configuration of a
 ///    scrollbar theme.
-class ScrollbarTheme extends InheritedWidget {
+class ScrollbarTheme extends InheritedTheme {
   /// Constructs a scrollbar theme that configures all descendant [Scrollbar]
   /// widgets.
   const ScrollbarTheme({
@@ -324,6 +324,11 @@ class ScrollbarTheme extends InheritedWidget {
     return scrollbarTheme?.data ?? Theme.of(context).scrollbarTheme;
   }
 
+  @override
+  Widget wrap(BuildContext context, Widget child) {
+    return ScrollbarTheme(data: data, child: child);
+  }
+
   @override
   bool updateShouldNotify(ScrollbarTheme oldWidget) => data != oldWidget.data;
 }

packages/flutter/test/material/menu_anchor_test.dart

@@ -9,6 +9,8 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import '../rendering/mock_canvas.dart';
+
 void main() {
   late MenuController controller;
   String? focusedMenu;
@@ -298,6 +300,101 @@ void main() {
     expect(iconRichText.text.style?.color, themeData.colorScheme.onSurface.withOpacity(0.38));
   });
 
+  testWidgets('Menu scrollbar inherits ScrollbarTheme', (WidgetTester tester) async {
+    const ScrollbarThemeData scrollbarTheme = ScrollbarThemeData(
+      thumbColor: MaterialStatePropertyAll<Color?>(Color(0xffff0000)),
+      thumbVisibility: MaterialStatePropertyAll<bool?>(true),
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: ThemeData(scrollbarTheme: scrollbarTheme),
+        home: Material(
+          child: MenuBar(
+            children: <Widget>[
+              SubmenuButton(
+                menuChildren: <Widget>[
+                  MenuItemButton(
+                    style: ButtonStyle(
+                      minimumSize: MaterialStateProperty.all<Size>(
+                        const Size.fromHeight(1000),
+                      ),
+                    ),
+                    onPressed: () {},
+                    child: const Text(
+                      'Category',
+                    ),
+                  ),
+                ],
+                child: const Text(
+                  'Main Menu',
+                ),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+
+    await tester.tap(find.text('Main Menu'));
+    await tester.pumpAndSettle();
+
+    expect(find.byType(Scrollbar), findsOneWidget);
+    // Test Scrollbar thumb color.
+    expect(
+      find.byType(Scrollbar),
+      paints..rrect(color: const Color(0xffff0000)),
+    );
+
+    // Close the menu.
+    await tester.tapAt(const Offset(10.0, 10.0));
+    await tester.pumpAndSettle();
+
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: ThemeData(scrollbarTheme: scrollbarTheme),
+        home: Material(
+          child: ScrollbarTheme(
+            data: scrollbarTheme.copyWith(
+              thumbColor: const MaterialStatePropertyAll<Color?>(Color(0xff00ff00)),
+            ),
+            child: MenuBar(
+              children: <Widget>[
+                SubmenuButton(
+                  menuChildren: <Widget>[
+                    MenuItemButton(
+                      style: ButtonStyle(
+                        minimumSize: MaterialStateProperty.all<Size>(
+                          const Size.fromHeight(1000),
+                        ),
+                      ),
+                      onPressed: () {},
+                      child: const Text(
+                        'Category',
+                      ),
+                    ),
+                  ],
+                  child: const Text(
+                    'Main Menu',
+                  ),
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+
+    await tester.tap(find.text('Main Menu'));
+    await tester.pumpAndSettle();
+
+    expect(find.byType(Scrollbar), findsOneWidget);
+    // Scrollbar thumb color should be updated.
+    expect(
+      find.byType(Scrollbar),
+      paints..rrect(color: const Color(0xff00ff00)),
+    );
+  }, variant: TargetPlatformVariant.desktop());
+
   group('Menu functions', () {
     testWidgets('basic menu structure', (WidgetTester tester) async {
       await tester.pumpWidget(

packages/flutter/test/material/popup_menu_test.dart

@@ -10,6 +10,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import '../rendering/mock_canvas.dart';
 import '../widgets/semantics_tester.dart';
 import 'feedback_tester.dart';
 
@@ -3098,6 +3099,94 @@ void main() {
     expect(nodeA().hasFocus, true);
     expect(nodeB().hasFocus, false);
   });
+
+  testWidgets('Popup menu scrollbar inherits ScrollbarTheme', (WidgetTester tester) async {
+    final Key popupButtonKey = UniqueKey();
+    const ScrollbarThemeData scrollbarTheme = ScrollbarThemeData(
+      thumbColor: MaterialStatePropertyAll<Color?>(Color(0xffff0000)),
+      thumbVisibility: MaterialStatePropertyAll<bool?>(true),
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: ThemeData(
+          scrollbarTheme: scrollbarTheme,
+          useMaterial3: true,
+        ),
+        home: Material(
+          child: Column(
+            children: <Widget>[
+              PopupMenuButton<void>(
+                key: popupButtonKey,
+                itemBuilder: (BuildContext context) {
+                  return <PopupMenuEntry<void>>[
+                    const PopupMenuItem<void>(
+                      height: 1000,
+                      child: Text('Example'),
+                    ),
+                  ];
+                },
+              ),
+            ],
+          ),
+        ),
+      )
+    );
+
+    await tester.tap(find.byKey(popupButtonKey));
+    await tester.pumpAndSettle();
+
+    expect(find.byType(Scrollbar), findsOneWidget);
+    // Test Scrollbar thumb color.
+    expect(
+      find.byType(Scrollbar),
+      paints..rrect(color: const Color(0xffff0000)),
+    );
+
+    // Close the menu.
+    await tester.tapAt(const Offset(20.0, 20.0));
+    await tester.pumpAndSettle();
+
+    // Test local ScrollbarTheme overrides global ScrollbarTheme.
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: ThemeData(
+          scrollbarTheme: scrollbarTheme,
+          useMaterial3: true,
+        ),
+        home: Material(
+          child: Column(
+            children: <Widget>[
+              ScrollbarTheme(
+                data: scrollbarTheme.copyWith(
+                  thumbColor: const MaterialStatePropertyAll<Color?>(Color(0xff0000ff)),
+                ),
+                child: PopupMenuButton<void>(
+                  key: popupButtonKey,
+                  itemBuilder: (BuildContext context) {
+                    return <PopupMenuEntry<void>>[
+                      const PopupMenuItem<void>(
+                        height: 1000,
+                        child: Text('Example'),
+                      ),
+                    ];
+                  },
+                ),
+              ),
+            ],
+          ),
+        ),
+      )
+    );
+    await tester.tap(find.byKey(popupButtonKey));
+    await tester.pumpAndSettle();
+
+    expect(find.byType(Scrollbar), findsOneWidget);
+    // Scrollbar thumb color should be updated.
+    expect(
+      find.byType(Scrollbar),
+      paints..rrect(color: const Color(0xff0000ff)),
+    );
+  }, variant: TargetPlatformVariant.desktop());
 }
 
 class TestApp extends StatelessWidget {