Yaru~~Dialog~~TitleBar: add support for leading & trailing widgets

example/lib/example_page_items.dart

@@ -121,8 +121,8 @@ final examplePageItems = <PageItem>[
     pageBuilder: (_) => const TilePage(),
   ),
   PageItem(
-    titleBuilder: (context) => const Text('YaruDialogTitle'),
-    tooltipMessage: 'YaruDialogTitle',
+    titleBuilder: (context) => const Text('YaruTitleBar'),
+    tooltipMessage: 'YaruTitleBar',
     iconBuilder: (context, selected) => selected
         ? const Icon(YaruIcons.information_filled)
         : const Icon(YaruIcons.information),

example/lib/pages/dialog_page.dart

@@ -39,23 +39,17 @@ class _DialogPageState extends State<DialogPage> {
                           )
                       ],
                       titlePadding: EdgeInsets.zero,
-                      title: YaruDialogTitle(
-                        title: Row(
-                          mainAxisSize: MainAxisSize.min,
-                          children: const [
-                            Text('The Title'),
-                            SizedBox(
-                              width: 10,
+                      title: YaruTitleBar(
+                        leading: const Center(
+                          child: SizedBox.square(
+                            dimension: 25,
+                            child: YaruCircularProgressIndicator(
+                              strokeWidth: 3,
                             ),
-                            SizedBox(
-                              height: 25,
-                              child: YaruCircularProgressIndicator(
-                                strokeWidth: 3,
-                              ),
-                            )
-                          ],
+                          ),
                         ),
-                        isCloseable: isCloseable,
+                        title: const Text('The Title'),
+                        trailing: YaruCloseButton(enabled: isCloseable),
                       ),
                       content: SizedBox(
                         height: 100,

lib/src/constants.dart

@@ -1,4 +1,5 @@
 const kYaruPagePadding = 20.0;
+const kYaruDialogTitleHeight = 72.0;
 const kYaruDialogTitlePadding = 0.0;
 const kYaruPageWidth = 500.0;
 const kYaruContainerRadius = 8.0;

lib/src/controls/yaru_title_bar.dart

@@ -0,0 +1,53 @@
+import 'package:flutter/material.dart';
+
+import '../constants.dart';
+import 'yaru_close_button.dart';
+
+/// A [Stack] of a [Widget] as [title] with a close button
+/// which pops the top-most route off the navigator
+/// that most tightly encloses the given context.
+///
+class YaruTitleBar extends StatelessWidget {
+  const YaruTitleBar({
+    super.key,
+    this.leading,
+    this.title,
+    this.trailing,
+    this.centerTitle = true,
+  });
+
+  /// The primary title widget.
+  final Widget? title;
+
+  /// A widget to display before the [title] widget.
+  final Widget? leading;
+
+  /// A widget to display after the [title] widget.
+  final Widget? trailing;
+
+  /// Whether the title should be centered.
+  final bool? centerTitle;
+
+  @override
+  Widget build(BuildContext context) {
+    return AppBar(
+      elevation: 0,
+      leading: leading,
+      automaticallyImplyLeading: false,
+      title: title,
+      centerTitle: centerTitle,
+      toolbarHeight: kYaruDialogTitleHeight,
+      backgroundColor: Colors.transparent,
+      titleTextStyle: Theme.of(context).dialogTheme.titleTextStyle,
+      actions: [
+        Padding(
+          padding: const EdgeInsets.all(5),
+          child: Align(
+            alignment: Alignment.topRight,
+            child: trailing ?? const YaruCloseButton(),
+          ),
+        ),
+      ],
+    );
+  }
+}

lib/yaru_widgets.dart

@@ -11,10 +11,9 @@ export 'src/controls/yaru_icon_button.dart';
 export 'src/controls/yaru_option_button.dart';
 export 'src/controls/yaru_progress_indicator.dart';
 export 'src/controls/yaru_radio_button.dart';
+export 'src/controls/yaru_title_bar.dart';
 export 'src/controls/yaru_toggle_button.dart';
 export 'src/controls/yaru_toggle_button_theme.dart';
-// Dialogs
-export 'src/dialogs/yaru_dialog_title.dart';
 // Extensions
 export 'src/extensions/border_radius_extension.dart';
 // Layouts