Users of ChangeNotifier should dispatch event of object creation in constructor. (#133210)

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

@@ -3355,6 +3355,13 @@ typedef _IndexWhereCallback = bool Function(_RouteEntry element);
 /// Acts as a ChangeNotifier and notifies after its List of _RouteEntries is
 /// mutated.
 class _History extends Iterable<_RouteEntry> with ChangeNotifier {
+  /// Creates an instance of [_History].
+  _History() {
+    if (kFlutterMemoryAllocationsEnabled) {
+      maybeDispatchObjectCreation();
+    }
+  }
+
   final List<_RouteEntry> _value = <_RouteEntry>[];
 
   int indexWhere(_IndexWhereCallback test, [int start = 0]) {

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

@@ -1567,6 +1567,13 @@ class _SelectableRegionContainerDelegate extends MultiSelectableSelectionContain
 /// This class optimize the selection update by keeping track of the
 /// [Selectable]s that currently contain the selection edges.
 abstract class MultiSelectableSelectionContainerDelegate extends SelectionContainerDelegate with ChangeNotifier {
+  /// Creates an instance of [MultiSelectableSelectionContainerDelegate].
+  MultiSelectableSelectionContainerDelegate() {
+    if (kFlutterMemoryAllocationsEnabled) {
+      maybeDispatchObjectCreation();
+    }
+  }
+
   /// Gets the list of selectables this delegate is managing.
   List<Selectable> selectables = <Selectable>[];
 

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

@@ -2895,6 +2895,13 @@ class _WidgetInspectorState extends State<WidgetInspector>
 
 /// Mutable selection state of the inspector.
 class InspectorSelection with ChangeNotifier {
+  /// Creates an instance of [InspectorSelection].
+  InspectorSelection() {
+    if (kFlutterMemoryAllocationsEnabled) {
+      maybeDispatchObjectCreation();
+    }
+  }
+
   /// Render objects that are candidates to be selected.
   ///
   /// Tools may wish to iterate through the list of candidates.

packages/flutter/test/foundation/change_notifier_test.dart

@@ -27,6 +27,12 @@ class A {
 }
 
 class B extends A with ChangeNotifier {
+  B() {
+    if (kFlutterMemoryAllocationsEnabled) {
+      maybeDispatchObjectCreation();
+    }
+  }
+
   @override
   void test() {
     notifyListeners();
@@ -35,6 +41,12 @@ class B extends A with ChangeNotifier {
 }
 
 class Counter with ChangeNotifier {
+  Counter() {
+    if (kFlutterMemoryAllocationsEnabled) {
+      maybeDispatchObjectCreation();
+    }
+  }
+
   int get value => _value;
   int _value = 0;
   set value(int value) {

packages/flutter/test/widgets/automatic_keep_alive_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/foundation.dart';
 import 'package:flutter/gestures.dart' show DragStartBehavior;
 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';
@@ -631,6 +632,12 @@ class RenderSliverMultiBoxAdaptorAlt extends RenderSliver with
 }
 
 class LeakCheckerHandle with ChangeNotifier {
+  LeakCheckerHandle() {
+    if (kFlutterMemoryAllocationsEnabled) {
+      maybeDispatchObjectCreation();
+    }
+  }
+
   @override
   bool get hasListeners => super.hasListeners;
 }

packages/flutter/test/widgets/route_notification_messages_test.dart

@@ -338,7 +338,11 @@ class SimpleRouterDelegate extends RouterDelegate<RouteInformation> with ChangeN
     required this.builder,
     this.onPopRoute,
     this.reportConfiguration = false,
-  });
+  }) {
+    if (kFlutterMemoryAllocationsEnabled) {
+      maybeDispatchObjectCreation();
+    }
+  }
 
   RouteInformation get routeInformation => _routeInformation;
   late RouteInformation _routeInformation;

packages/flutter/test/widgets/router_restoration_test.dart

@@ -90,6 +90,12 @@ class _TestRouteInformationParser extends RouteInformationParser<String> {
 }
 
 class _TestRouterDelegate extends RouterDelegate<String> with ChangeNotifier {
+  _TestRouterDelegate() {
+    if (kFlutterMemoryAllocationsEnabled) {
+      maybeDispatchObjectCreation();
+    }
+  }
+
   final List<String> newRoutePaths = <String>[];
   final List<String> restoredRoutePaths = <String>[];
 
@@ -128,6 +134,12 @@ class _TestRouterDelegate extends RouterDelegate<String> with ChangeNotifier {
 }
 
 class _TestRouteInformationProvider extends RouteInformationProvider with ChangeNotifier {
+  _TestRouteInformationProvider() {
+    if (kFlutterMemoryAllocationsEnabled) {
+      maybeDispatchObjectCreation();
+    }
+  }
+
   @override
   RouteInformation get value => _value;
   RouteInformation _value = RouteInformation(uri: Uri.parse('/home'));

packages/flutter/test/widgets/router_test.dart

@@ -1633,7 +1633,11 @@ class SimpleRouterDelegate extends RouterDelegate<RouteInformation> with ChangeN
     this.builder,
     this.onPopRoute,
     this.reportConfiguration = false,
-  });
+  }) {
+    if (kFlutterMemoryAllocationsEnabled) {
+      maybeDispatchObjectCreation();
+    }
+  }
 
   RouteInformation? get routeInformation => _routeInformation;
   RouteInformation? _routeInformation;
@@ -1717,7 +1721,11 @@ class SimpleNavigatorRouterDelegate extends RouterDelegate<RouteInformation> wit
 class SimpleRouteInformationProvider extends RouteInformationProvider with ChangeNotifier {
   SimpleRouteInformationProvider({
     this.onRouterReport,
-  });
+  }) {
+    if (kFlutterMemoryAllocationsEnabled) {
+      maybeDispatchObjectCreation();
+    }
+  }
 
   RouterReportRouterInformation? onRouterReport;
 
@@ -1773,7 +1781,11 @@ class CompleterRouteInformationParser extends RouteInformationParser<RouteInform
 class SimpleAsyncRouterDelegate extends RouterDelegate<RouteInformation> with ChangeNotifier {
   SimpleAsyncRouterDelegate({
     required this.builder,
-  });
+  }) {
+    if (kFlutterMemoryAllocationsEnabled) {
+      maybeDispatchObjectCreation();
+    }
+  }
 
   RouteInformation? get routeInformation => _routeInformation;
   RouteInformation? _routeInformation;