HeroController should dispatch creation and disposal events. (#137835)

packages/flutter/lib/src/cupertino/tab_view.dart

@@ -156,6 +156,12 @@ class _CupertinoTabViewState extends State<CupertinoTabView> {
     }
   }
 
+  @override
+  void dispose() {
+    _heroController.dispose();
+    super.dispose();
+  }
+
   void _updateObservers() {
     _navigatorObservers =
         List<NavigatorObserver>.of(widget.navigatorObservers)

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

@@ -784,7 +784,17 @@ class HeroController extends NavigatorObserver {
   ///
   /// The [createRectTween] argument is optional. If null, the controller uses a
   /// linear [Tween<Rect>].
-  HeroController({ this.createRectTween });
+  HeroController({ this.createRectTween }) {
+    // TODO(polina-c): stop duplicating code across disposables
+    // https://github.com/flutter/flutter/issues/137435
+    if (kFlutterMemoryAllocationsEnabled) {
+      MemoryAllocations.instance.dispatchObjectCreated(
+        library: 'package:flutter/widgets.dart',
+        className: '$HeroController',
+        object: this,
+      );
+    }
+  }
 
   /// Used to create [RectTween]s that interpolate the position of heroes in flight.
   ///
@@ -1043,6 +1053,12 @@ class HeroController extends NavigatorObserver {
   /// Releases resources.
   @mustCallSuper
   void dispose() {
+    // TODO(polina-c): stop duplicating code across disposables
+    // https://github.com/flutter/flutter/issues/137435
+    if (kFlutterMemoryAllocationsEnabled) {
+      MemoryAllocations.instance.dispatchObjectDisposed(object: this);
+    }
+
     for (final _HeroFlight flight in _flights.values) {
       flight.dispose();
     }

packages/flutter/test/material/app_test.dart

@@ -1060,6 +1060,7 @@ void main() {
 
   testWidgetsWithLeakTracking('MaterialApp does create HeroController with the MaterialRectArcTween', (WidgetTester tester) async {
     final HeroController controller = MaterialApp.createMaterialHeroController();
+    addTearDown(controller.dispose);
     final Tween<Rect?> tween = controller.createRectTween!(
       const Rect.fromLTRB(0.0, 0.0, 10.0, 10.0),
       const Rect.fromLTRB(0.0, 0.0, 20.0, 20.0),

packages/flutter/test/widgets/heroes_test.dart

@@ -304,9 +304,12 @@ Future<void> main() async {
   testWidgetsWithLeakTracking('Heroes still animate after hero controller is swapped.', (WidgetTester tester) async {
     final GlobalKey<NavigatorState> key = GlobalKey<NavigatorState>();
     final UniqueKey heroKey = UniqueKey();
+    final HeroController controller1 = HeroController();
+    addTearDown(controller1.dispose);
+
     await tester.pumpWidget(
       HeroControllerScope(
-        controller: HeroController(),
+        controller: controller1,
         child: TestDependencies(
           child: Navigator(
             key: key,
@@ -352,15 +355,19 @@ Future<void> main() async {
         );
       },
     ));
+
     expect(find.byKey(heroKey), findsNothing);
     // Begins the navigation
     await tester.pump();
     await tester.pump(const Duration(milliseconds: 30));
     expect(find.byKey(heroKey), isOnstage);
+    final HeroController controller2 = HeroController();
+    addTearDown(controller2.dispose);
+
     // Pumps a new hero controller.
     await tester.pumpWidget(
       HeroControllerScope(
-        controller: HeroController(),
+        controller: controller2,
         child: TestDependencies(
           child: Navigator(
             key: key,
@@ -389,6 +396,7 @@ Future<void> main() async {
         ),
       ),
     );
+
     // The original animation still flies.
     expect(find.byKey(heroKey), isOnstage);
     // Waits for the animation finishes.
@@ -3135,6 +3143,13 @@ Future<void> main() async {
     await tester.pumpAndSettle();
     expect(tester.getTopLeft(find.byType(Image)).dy, moreOrLessEquals(forwardRest, epsilon: 0.1));
   });
+
+  test('HeroController dispatches memory events', () async {
+    await expectLater(
+      await memoryEvents(() => HeroController().dispose(), HeroController),
+      areCreateAndDispose,
+    );
+  });
 }
 
 class TestDependencies extends StatelessWidget {

packages/flutter/test/widgets/navigator_test.dart

@@ -2367,6 +2367,8 @@ void main() {
           ),
         );
       };
+    addTearDown(spy.dispose);
+
     await tester.pumpWidget(
       HeroControllerScope(
         controller: spy,
@@ -2437,6 +2439,8 @@ void main() {
           ),
         );
       };
+    addTearDown(spy.dispose);
+
     await tester.pumpWidget(
       HeroControllerScope(
         controller: spy,
@@ -2506,6 +2510,7 @@ void main() {
           ),
         );
       };
+    addTearDown(spy1.dispose);
     final List<NavigatorObservation> observations2 = <NavigatorObservation>[];
     final HeroControllerSpy spy2 = HeroControllerSpy()
       ..onPushed = (Route<dynamic>? route, Route<dynamic>? previousRoute) {
@@ -2517,6 +2522,8 @@ void main() {
           ),
         );
       };
+    addTearDown(spy2.dispose);
+
     await tester.pumpWidget(
       TestDependencies(
         child: Stack(
@@ -2633,6 +2640,8 @@ void main() {
 
   testWidgetsWithLeakTracking('hero controller subscribes to multiple navigators does throw', (WidgetTester tester) async {
     final HeroControllerSpy spy = HeroControllerSpy();
+    addTearDown(spy.dispose);
+
     await tester.pumpWidget(
       HeroControllerScope(
         controller: spy,
@@ -2671,6 +2680,8 @@ void main() {
 
   testWidgetsWithLeakTracking('hero controller throws has correct error message', (WidgetTester tester) async {
     final HeroControllerSpy spy = HeroControllerSpy();
+    addTearDown(spy.dispose);
+
     await tester.pumpWidget(
       HeroControllerScope(
         controller: spy,