Fix Material 3 AppBar.leading action IconButtons (#154512)

Fixes [`AppBar` back button focus/hover circle should not fill up whole height](https://github.com/flutter/flutter/issues/141361)
Fixes [[Material 3] Date Range Picker close button has incorrect shape](https://github.com/flutter/flutter/issues/154393)

This updates the leading condition added in https://github.com/flutter/flutter/pull/110722

### Code sample

<details>
<summary>expand to view the code sample</summary> 

```dart
import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: SingleChildScrollView(
          child: Column(
            children: [
              Column(
                spacing: 10.0,
                mainAxisSize: MainAxisSize.min,
                children: <Widget>[
                  AppBar(
                    leading: BackButton(
                      style: IconButton.styleFrom(backgroundColor: Colors.red),
                    ),
                    backgroundColor: Theme.of(context).colorScheme.secondaryContainer,
                    title: const Text('AppBar with BackButton'),
                  ),
                  AppBar(
                    leading: CloseButton(
                      style: IconButton.styleFrom(backgroundColor: Colors.red),
                    ),
                    backgroundColor: Theme.of(context).colorScheme.secondaryContainer,
                    title: const Text('AppBar with CloseButton'),
                  ),
                  AppBar(
                    leading: DrawerButton(
                      style: IconButton.styleFrom(backgroundColor: Colors.red),
                    ),
                    backgroundColor: Theme.of(context).colorScheme.secondaryContainer,
                    title: const Text('AppBar with DrawerButton'),
                  ),
                ],
              ),
              const Divider(),
              Column(
                spacing: 10.0,
                mainAxisSize: MainAxisSize.min,
                children: <Widget>[
                  AppBar(
                    leading: BackButton(
                      style: IconButton.styleFrom(backgroundColor: Colors.red),
                    ),
                    backgroundColor: Theme.of(context).colorScheme.secondaryContainer,
                    toolbarHeight: 100.0,
                    title: const Text('AppBar with custom height'),
                  ),
                  AppBar(
                    leading: CloseButton(
                      style: IconButton.styleFrom(backgroundColor: Colors.red),
                    ),
                    backgroundColor: Theme.of(context).colorScheme.secondaryContainer,
                    toolbarHeight: 100.0,
                    title: const Text('AppBar with custom height'),
                  ),
                  AppBar(
                    leading: DrawerButton(
                      style: IconButton.styleFrom(backgroundColor: Colors.red),
                    ),
                    backgroundColor: Theme.of(context).colorScheme.secondaryContainer,
                    toolbarHeight: 100.0,
                    title: const Text('AppBar with custom height'),
                  ),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }
}
```

</details>

### Before

<img width="912" alt="Screenshot 2024-09-04 at 12 38 05" src="https://github.com/user-attachments/assets/25a6893c-89c9-4b45-a5bb-8da0eee71cd2">

### After

<img width="912" alt="Screenshot 2024-09-04 at 12 38 28" src="https://github.com/user-attachments/assets/49727183-568c-412e-9fa1-1eefd0cd87a7">

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

@@ -21,42 +21,17 @@ import 'material_localizations.dart';
 import 'scaffold.dart';
 import 'theme.dart';
 
-abstract class _ActionButton extends StatelessWidget {
+abstract class _ActionButton extends IconButton {
   /// Creates a Material Design icon button.
   const _ActionButton({
     super.key,
-    this.color,
+    super.color,
-    required this.icon,
+    super.style,
-    required this.onPressed,
+    super.onPressed,
+    required super.icon,
     this.standardComponent,
-    this.style,
   });
 
-  /// The icon to display inside the button.
-  final Widget icon;
-
-  /// The callback that is called when the button is tapped
-  /// or otherwise activated.
-  ///
-  /// If this is set to null, the button will do a default action
-  /// when it is tapped or activated.
-  final VoidCallback? onPressed;
-
-  /// The color to use for the icon.
-  ///
-  /// Defaults to the [IconThemeData.color] specified in the ambient [IconTheme],
-  /// which usually matches the ambient [Theme]'s [ThemeData.iconTheme].
-  final Color? color;
-
-  /// Customizes this icon button's appearance.
-  ///
-  /// The [style] is only used for Material 3 [IconButton]s. If [ThemeData.useMaterial3]
-  /// is set to true, [style] is preferred for icon button customization, and any
-  /// parameters defined in [style] will override the same parameters in [IconButton].
-  ///
-  /// Null by default.
-  final ButtonStyle? style;
-
   /// An enum value to use to identify this button as a type of
   /// [StandardComponentType].
   final StandardComponentType? standardComponent;

packages/flutter/test/material/app_bar_sliver_test.dart

@@ -108,7 +108,11 @@ void main() {
       await tester.pumpAndSettle();
 
       final Finder collapsedTitle = find.text(title).last;
-      final Offset backButtonOffset = tester.getTopRight(find.byType(BackButton));
+      // Get the offset of the Center widget that wraps the IconButton.
+      final Offset backButtonOffset = tester.getTopRight(find.ancestor(
+        of: find.byType(IconButton),
+        matching: find.byType(Center),
+      ));
       final Offset titleOffset = tester.getTopLeft(collapsedTitle);
       expect(titleOffset.dx, backButtonOffset.dx + titleSpacing);
   });

packages/flutter/test/material/app_bar_test.dart

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
@@ -16,6 +17,7 @@ TextStyle? _iconStyle(WidgetTester tester, IconData icon) {
   );
   return iconRichText.text.style;
 }
+
 void main() {
   setUp(() {
     debugResetSemanticsIdCounter();
@@ -2968,6 +2970,203 @@ void main() {
     });
   });
 
+  testWidgets('AppBar.leading size with custom IconButton', (WidgetTester tester) async {
+    final Key leadingKey = UniqueKey();
+    final Key titleKey = UniqueKey();
+    const double titleSpacing = 16.0;
+    final ThemeData theme = ThemeData();
+
+    await tester.pumpWidget(MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(
+          leading: IconButton(
+            key: leadingKey,
+            onPressed: () {},
+            icon: const Icon(Icons.menu),
+          ),
+          centerTitle: false,
+          title: Text(
+            'Title',
+            key: titleKey,
+          ),
+        ),
+      ),
+    ));
+
+    final Finder buttonFinder = find.byType(IconButton);
+    expect(tester.getSize(buttonFinder), const Size(48.0, 48.0));
+
+    final TestGesture gesture = await tester.createGesture(
+      kind: PointerDeviceKind.mouse,
+    );
+    await gesture.addPointer();
+    await gesture.moveTo(tester.getCenter(buttonFinder));
+    await tester.pumpAndSettle();
+    expect(
+      buttonFinder,
+      paints
+        ..rect(
+          rect: const Rect.fromLTRB(0.0, 0.0, 40.0, 40.0),
+          color: theme.colorScheme.onSurface.withOpacity(0.08),
+        ),
+    );
+
+    // Get the offset of the Center widget that wraps the IconButton.
+    final Offset backButtonOffset = tester.getTopRight(find.ancestor(
+      of: buttonFinder,
+      matching: find.byType(Center),
+    ));
+    final Offset titleOffset = tester.getTopLeft(find.byKey(titleKey));
+    expect(titleOffset.dx, backButtonOffset.dx + titleSpacing);
+  });
+
+  testWidgets('AppBar.leading size with custom BackButton', (WidgetTester tester) async {
+    final Key leadingKey = UniqueKey();
+    final Key titleKey = UniqueKey();
+    const double titleSpacing = 16.0;
+    final ThemeData theme = ThemeData();
+
+    await tester.pumpWidget(MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(
+          leading: BackButton(
+            key: leadingKey,
+            onPressed: () {},
+          ),
+          centerTitle: false,
+          title: Text(
+            'Title',
+            key: titleKey,
+          ),
+        ),
+      ),
+    ));
+
+    final Finder buttonFinder = find.byType(BackButton);
+    expect(tester.getSize(buttonFinder), const Size(48.0, 48.0));
+
+    final TestGesture gesture = await tester.createGesture(
+      kind: PointerDeviceKind.mouse,
+    );
+    await gesture.addPointer();
+    await gesture.moveTo(tester.getCenter(buttonFinder));
+    await tester.pumpAndSettle();
+    expect(
+      buttonFinder,
+      paints
+        ..rect(
+          rect: const Rect.fromLTRB(0.0, 0.0, 40.0, 40.0),
+          color: theme.colorScheme.onSurface.withOpacity(0.08),
+        ),
+    );
+
+    // Get the offset of the Center widget that wraps the IconButton.
+    final Offset backButtonOffset = tester.getTopRight(find.ancestor(
+      of: buttonFinder,
+      matching: find.byType(Center),
+    ));
+    final Offset titleOffset = tester.getTopLeft(find.byKey(titleKey));
+    expect(titleOffset.dx, backButtonOffset.dx + titleSpacing);
+  });
+
+  testWidgets('AppBar.leading size with custom CloseButton', (WidgetTester tester) async {
+    final Key leadingKey = UniqueKey();
+    final Key titleKey = UniqueKey();
+    const double titleSpacing = 16.0;
+    final ThemeData theme = ThemeData();
+
+    await tester.pumpWidget(MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(
+          leading: CloseButton(
+            key: leadingKey,
+            onPressed: () {},
+          ),
+          centerTitle: false,
+          title: Text(
+            'Title',
+            key: titleKey,
+          ),
+        ),
+      ),
+    ));
+
+    final Finder buttonFinder = find.byType(CloseButton);
+    expect(tester.getSize(buttonFinder), const Size(48.0, 48.0));
+
+    final TestGesture gesture = await tester.createGesture(
+      kind: PointerDeviceKind.mouse,
+    );
+    await gesture.addPointer();
+    await gesture.moveTo(tester.getCenter(buttonFinder));
+    await tester.pumpAndSettle();
+    expect(
+      buttonFinder,
+      paints
+        ..rect(
+          rect: const Rect.fromLTRB(0.0, 0.0, 40.0, 40.0),
+          color: theme.colorScheme.onSurface.withOpacity(0.08),
+        ),
+    );
+
+    // Get the offset of the Center widget that wraps the IconButton.
+    final Offset backButtonOffset = tester.getTopRight(find.ancestor(
+      of: buttonFinder,
+      matching: find.byType(Center),
+    ));
+    final Offset titleOffset = tester.getTopLeft(find.byKey(titleKey));
+    expect(titleOffset.dx, backButtonOffset.dx + titleSpacing);
+  });
+
+  testWidgets('AppBar.leading size with custom DrawerButton', (WidgetTester tester) async {
+    final Key leadingKey = UniqueKey();
+    final Key titleKey = UniqueKey();
+    const double titleSpacing = 16.0;
+    final ThemeData theme = ThemeData();
+
+    await tester.pumpWidget(MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(
+          leading: DrawerButton(
+            key: leadingKey,
+            onPressed: () {},
+          ),
+          centerTitle: false,
+          title: Text(
+            'Title',
+            key: titleKey,
+          ),
+        ),
+      ),
+    ));
+
+    final Finder buttonFinder = find.byType(DrawerButton);
+    expect(tester.getSize(buttonFinder), const Size(48.0, 48.0));
+
+    final TestGesture gesture = await tester.createGesture(
+      kind: PointerDeviceKind.mouse,
+    );
+    await gesture.addPointer();
+    await gesture.moveTo(tester.getCenter(buttonFinder));
+    await tester.pumpAndSettle();
+    expect(
+      buttonFinder,
+      paints
+        ..rect(
+          rect: const Rect.fromLTRB(0.0, 0.0, 40.0, 40.0),
+          color: theme.colorScheme.onSurface.withOpacity(0.08),
+        ),
+    );
+
+    // Get the offset of the Center widget that wraps the IconButton.
+    final Offset backButtonOffset = tester.getTopRight(find.ancestor(
+      of: buttonFinder,
+      matching: find.byType(Center),
+    ));
+    final Offset titleOffset = tester.getTopLeft(find.byKey(titleKey));
+    expect(titleOffset.dx, backButtonOffset.dx + titleSpacing);
+  });
+
   group('Material 2', () {
     testWidgets('Material2 - AppBar draws a light system bar for a dark background', (WidgetTester tester) async {
       final ThemeData darkTheme = ThemeData.dark(useMaterial3: false);

packages/flutter/test/material/date_range_picker_test.dart

@@ -127,7 +127,10 @@ void main() {
       expect(saveText, findsOneWidget);
 
       // Test the close button position.
-      final Offset closeButtonBottomRight = tester.getBottomRight(find.byType(CloseButton));
+      final Offset closeButtonBottomRight = tester.getBottomRight(find.ancestor(
+        of: find.byType(IconButton),
+        matching: find.byType(Center),
+      ));
       final Offset helpTextTopLeft = tester.getTopLeft(helpText);
       expect(closeButtonBottomRight.dx, 56.0);
       expect(closeButtonBottomRight.dy, helpTextTopLeft.dy);
@@ -1592,6 +1595,30 @@ void main() {
     await tester.pumpAndSettle();
   });
 
+  // This is a regression test for https://github.com/flutter/flutter/issues/154393.
+  testWidgets('DateRangePicker close button shape should be square', (WidgetTester tester) async {
+    await preparePicker(tester, (Future<DateTimeRange?> range) async {
+      final ThemeData theme = ThemeData();
+      final Finder buttonFinder = find.widgetWithIcon(IconButton, Icons.close);
+      expect(tester.getSize(buttonFinder), const Size(48.0, 48.0));
+
+      // Test the close button overlay size is square.
+      final TestGesture gesture = await tester.createGesture(
+        kind: PointerDeviceKind.mouse,
+      );
+      await gesture.addPointer();
+      await gesture.moveTo(tester.getCenter(buttonFinder));
+      await tester.pumpAndSettle();
+      expect(
+        buttonFinder,
+        paints
+          ..rect(
+            rect: const Rect.fromLTRB(0.0, 0.0, 40.0, 40.0),
+            color: theme.colorScheme.onSurfaceVariant.withOpacity(0.08),
+          ),
+      );
+    }, useMaterial3: true);
+  });
 
   group('Material 2', () {
     // These tests are only relevant for Material 2. Once Material 2