RestorableProperty should dispatch creation in constructor. (#133883)

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

@@ -454,6 +454,13 @@ class _RootRestorationScopeState extends State<RootRestorationScope> {
 ///  * [RestorationManager], which describes how state restoration works in
 ///    Flutter.
 abstract class RestorableProperty<T> extends ChangeNotifier {
+  /// Creates a [RestorableProperty].
+  RestorableProperty(){
+    if (kFlutterMemoryAllocationsEnabled) {
+      maybeDispatchObjectCreation();
+    }
+  }
+
   /// Called by the [RestorationMixin] if no restoration data is available to
   /// restore the value of the property from to obtain the default value for the
   /// property.

packages/flutter/test/material/time_test.dart

@@ -58,7 +58,9 @@ void main() {
 
   group('RestorableTimeOfDay tests', () {
     testWidgetsWithLeakTracking('value is not accessible when not registered', (WidgetTester tester) async {
-      expect(() => RestorableTimeOfDay(const TimeOfDay(hour: 20, minute: 4)).value, throwsAssertionError);
+      final RestorableTimeOfDay property = RestorableTimeOfDay(const TimeOfDay(hour: 20, minute: 4));
+      addTearDown(() => property.dispose());
+      expect(() => property.value, throwsAssertionError);
     });
 
     testWidgets('work when not in restoration scope', (WidgetTester tester) async {

packages/flutter/test/widgets/restorable_property_test.dart

@@ -4,6 +4,7 @@
 
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:leak_tracker_flutter_testing/leak_tracker_flutter_testing.dart';
 
 void main() {
   testWidgets('value is not accessible when not registered', (WidgetTester tester) async {
@@ -25,6 +26,10 @@ void main() {
     expect(() => _TestRestorableValue().value, throwsAssertionError);
   });
 
+  testWidgetsWithLeakTracking('$RestorableProperty dispatches creation in constructor', (WidgetTester widgetTester) async {
+    expect(()=> RestorableDateTimeN(null).dispose(), dispatchesMemoryEvents(RestorableDateTimeN));
+  });
+
   testWidgets('work when not in restoration scope', (WidgetTester tester) async {
     await tester.pumpWidget(const _RestorableWidget());