close all tabs prompt

app/lib/features/geckoview/features/browser/presentation/widgets/sheets/view_tabs.dart

@@ -186,11 +186,39 @@ class _TabSheetHeader extends HookConsumerWidget {
                     TextButton.icon(
                       onPressed: () async {
                         final container = ref.read(selectedContainerProvider);
+                        final result = await showDialog<bool?>(
+                          context: context,
+                          builder: (BuildContext context) {
+                            return AlertDialog(
+                              title: const Text('Close All Tabs'),
+                              content: Text(
+                                (container != null)
+                                    ? 'Are you sure you want to close all container tabs?'
+                                    : 'Are you sure you want to close all unassigned tabs?',
+                              ),
+                              actions: <Widget>[
+                                TextButton(
+                                  onPressed: () {
+                                    Navigator.pop(context, false);
+                                  },
+                                  child: const Text('Cancel'),
+                                ),
+                                TextButton(
+                                  onPressed: () {
+                                    Navigator.pop(context, true);
+                                  },
+                                  child: const Text('Close'),
+                                ),
+                              ],
+                            );
+                          },
+                        );
+
+                        if (result == true) {
                         await ref
                             .read(tabDataRepositoryProvider.notifier)
                             .closeAllTabsByContainer(container);
-
-                        onClose();
+                        }
                       },
                       icon: const Icon(MdiIcons.closeBoxMultiple),
                       label: const Text('Close All'),