Custom context menus in SelectableRegion on web (#121653)

contextMenuBuilder now works with SelectableRegion on web (when using BrowserContextMenu.disable).

packages/flutter/lib/src/widgets/selectable_region.dart

@@ -738,10 +738,11 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
     }
 
     // Web is using native dom elements to enable clipboard functionality of the
-    // toolbar: copy, paste, select, cut. It might also provide additional
-    // functionality depending on the browser (such as translate). Due to this
-    // we should not show a Flutter toolbar for the editable text elements.
-    if (kIsWeb) {
+    // context menu: copy, paste, select, cut. It might also provide additional
+    // functionality depending on the browser (such as translate). Due to this,
+    // we should not show a Flutter toolbar for the editable text elements
+    // unless the browser's context menu is explicitly disabled.
+    if (kIsWeb && BrowserContextMenu.enabled) {
       return false;
     }
 

packages/flutter/test/widgets/editable_text_test.dart

@@ -1676,7 +1676,7 @@ void main() {
       SystemChannels.contextMenu.setMockMethodCallHandler(null);
     });
 
-    testWidgets('web can show toolbar when the browser context menu is disabled', (WidgetTester tester) async {
+    testWidgets('web can show flutter context menu when the browser context menu is disabled', (WidgetTester tester) async {
       await tester.pumpWidget(
         MaterialApp(
           home: EditableText(

packages/flutter/test/widgets/selectable_region_test.dart

@@ -1781,6 +1781,51 @@ void main() {
     expect(content, isNotNull);
     expect(content!.plainText, 'How');
   });
+
+  group('BrowserContextMenu', () {
+    setUp(() async {
+      SystemChannels.contextMenu.setMockMethodCallHandler((MethodCall call) {
+        // Just complete successfully, so that BrowserContextMenu thinks that
+        // the engine successfully received its call.
+        return Future<void>.value();
+      });
+      await BrowserContextMenu.disableContextMenu();
+    });
+
+    tearDown(() async {
+      await BrowserContextMenu.enableContextMenu();
+      SystemChannels.contextMenu.setMockMethodCallHandler(null);
+    });
+
+    testWidgets('web can show flutter context menu when the browser context menu is disabled', (WidgetTester tester) async {
+      await tester.pumpWidget(
+        MaterialApp(
+          home: SelectableRegion(
+            onSelectionChanged: (SelectedContent? selectedContent) {},
+            focusNode: FocusNode(),
+            selectionControls: materialTextSelectionControls,
+            child: const Center(
+              child: Text('How are you'),
+            ),
+          ),
+        ),
+      );
+
+      final SelectableRegionState state =
+          tester.state<SelectableRegionState>(find.byType(SelectableRegion));
+      expect(find.text('Copy'), findsNothing);
+
+      state.selectAll(SelectionChangedCause.toolbar);
+      await tester.pumpAndSettle();
+      expect(find.text('Copy'), findsOneWidget);
+
+      state.hideToolbar();
+      await tester.pumpAndSettle();
+      expect(find.text('Copy'), findsNothing);
+    },
+      skip: !kIsWeb, // [intended]
+    );
+  });
 }
 
 class SelectionSpy extends LeafRenderObjectWidget {