Allow DoNothingIntent and DoNothingAndStopPropagationIntent to be used in a const environment (#105983)

Author: dkwingsmt

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

@@ -1342,7 +1342,7 @@ class VoidCallbackAction extends Action<VoidCallbackIntent> {
 ///    handlers in the focus chain.
 class DoNothingIntent extends Intent {
   /// Creates a const [DoNothingIntent].
-  factory DoNothingIntent() => const DoNothingIntent._();
+  const factory DoNothingIntent() = DoNothingIntent._;
 
   // Make DoNothingIntent constructor private so it can't be subclassed.
   const DoNothingIntent._();
@@ -1367,7 +1367,7 @@ class DoNothingIntent extends Intent {
 ///  * [DoNothingIntent], a similar intent that will handle the key event.
 class DoNothingAndStopPropagationIntent extends Intent {
   /// Creates a const [DoNothingAndStopPropagationIntent].
-  factory DoNothingAndStopPropagationIntent() => const DoNothingAndStopPropagationIntent._();
+  const factory DoNothingAndStopPropagationIntent() = DoNothingAndStopPropagationIntent._;
 
   // Make DoNothingAndStopPropagationIntent constructor private so it can't be subclassed.
   const DoNothingAndStopPropagationIntent._();

packages/flutter/test/widgets/actions_test.dart

@@ -120,7 +120,7 @@ void main() {
       await tester.pump();
       final Object? result = Actions.maybeInvoke(
         containerKey.currentContext!,
-        DoNothingIntent(),
+        const DoNothingIntent(),
       );
       expect(result, isNull);
       expect(invoked, isFalse);
@@ -146,7 +146,7 @@ void main() {
       await tester.pump();
       final Object? result = Actions.maybeInvoke(
         containerKey.currentContext!,
-        DoNothingIntent(),
+        const DoNothingIntent(),
       );
       expect(result, isNull);
       expect(invoked, isFalse);

packages/flutter/test/widgets/shortcuts_test.dart

@@ -871,7 +871,7 @@ void main() {
                 },
                 child: Shortcuts(
                   shortcuts: <LogicalKeySet, Intent>{
-                    LogicalKeySet(LogicalKeyboardKey.keyA): DoNothingAndStopPropagationIntent(),
+                    LogicalKeySet(LogicalKeyboardKey.keyA): const DoNothingAndStopPropagationIntent(),
                   },
                   child: TextField(key: textFieldKey, autofocus: true),
                 ),
@@ -1710,17 +1710,17 @@ void main() {
 
     testWidgets('using a disposed token asserts', (WidgetTester tester) async {
       final ShortcutRegistry registry = ShortcutRegistry();
-      final ShortcutRegistryEntry token = registry.addAll(<ShortcutActivator, Intent>{
-        const SingleActivator(LogicalKeyboardKey.keyA): DoNothingIntent(),
+      final ShortcutRegistryEntry token = registry.addAll(const <ShortcutActivator, Intent>{
+        SingleActivator(LogicalKeyboardKey.keyA): DoNothingIntent(),
       });
       token.dispose();
       expect(() {token.replaceAll(<ShortcutActivator, Intent>{}); }, throwsFlutterError);
     });
 
     testWidgets('setting duplicate bindings asserts', (WidgetTester tester) async {
       final ShortcutRegistry registry = ShortcutRegistry();
-      final ShortcutRegistryEntry token = registry.addAll(<ShortcutActivator, Intent>{
-        const SingleActivator(LogicalKeyboardKey.keyA): DoNothingIntent(),
+      final ShortcutRegistryEntry token = registry.addAll(const <ShortcutActivator, Intent>{
+        SingleActivator(LogicalKeyboardKey.keyA): DoNothingIntent(),
       });
       expect(() {
         final ShortcutRegistryEntry token2 = registry.addAll(const <ShortcutActivator, Intent>{