Create helper method to dispatch object creation and disposal. (#163637)

Contributes to https://github.com/flutter/flutter/issues/137435.

Will test cover and convert to 'ready for review' after getting
agreement about the refactoring.

packages/flutter/lib/src/animation/animations.dart

@@ -379,15 +379,9 @@ class ReverseAnimation extends Animation<double>
 class CurvedAnimation extends Animation<double> with AnimationWithParentMixin<double> {
   /// Creates a curved animation.
   CurvedAnimation({required this.parent, required this.curve, this.reverseCurve}) {
-    // TODO(polina-c): stop duplicating code across disposables
-    // https://github.com/flutter/flutter/issues/137435
-    if (kFlutterMemoryAllocationsEnabled) {
-      FlutterMemoryAllocations.instance.dispatchObjectCreated(
-        library: 'package:flutter/animation.dart',
-        className: '$CurvedAnimation',
-        object: this,
-      );
-    }
+    assert(
+      debugMaybeDispatchObjectCreated('package:flutter/animation.dart', 'CurvedAnimation', this),
+    );
     _updateCurveDirection(parent.status);
     parent.addStatusListener(_updateCurveDirection);
   }
@@ -434,11 +428,7 @@ class CurvedAnimation extends Animation<double> with AnimationWithParentMixin<do
 
   /// Cleans up any listeners added by this CurvedAnimation.
   void dispose() {
-    // TODO(polina-c): stop duplicating code across disposables
-    // https://github.com/flutter/flutter/issues/137435
-    if (kFlutterMemoryAllocationsEnabled) {
-      FlutterMemoryAllocations.instance.dispatchObjectDisposed(object: this);
-    }
+    assert(debugMaybeDispatchObjectDisposed(this));
     isDisposed = true;
     parent.removeStatusListener(_updateCurveDirection);
   }

packages/flutter/lib/src/foundation/debug.dart

@@ -12,6 +12,7 @@ library;
 import 'dart:ui' as ui show Brightness;
 
 import 'assertions.dart';
+import 'memory_allocations.dart';
 import 'platform.dart';
 import 'print.dart';
 
@@ -132,3 +133,35 @@ String? activeDevToolsServerAddress;
 
 /// The uri for the connected vm service protocol.
 String? connectedVmServiceUri;
+
+/// If memory allocation tracking is enabled, dispatch object creation.
+///
+/// This method is not member of FlutterMemoryAllocations, because
+/// [FlutterMemoryAllocations] should not increase size of the Flutter application
+/// if memory allocations are disabled.
+///
+/// Should be called only from within an assert.
+///
+/// Returns true to make it easier to be wrapped into `assert`.
+bool debugMaybeDispatchObjectCreated(String library, String className, Object object) {
+  if (kFlutterMemoryAllocationsEnabled) {
+    FlutterMemoryAllocations.instance.dispatchObjectCreated(
+      library: library,
+      className: className,
+      object: object,
+    );
+  }
+  return true;
+}
+
+/// If memory allocations tracking is enabled, dispatch object disposal.
+///
+/// Should be called only from within an assert.
+///
+/// Returns true to make it easier to be wrapped into `assert`.
+bool debugMaybeDispatchObjectDisposed(Object object) {
+  if (kFlutterMemoryAllocationsEnabled) {
+    FlutterMemoryAllocations.instance.dispatchObjectDisposed(object: object);
+  }
+  return true;
+}

packages/flutter/test/foundation/debug_test.dart

@@ -47,4 +47,57 @@ void main() {
       expect(printBuffer.toString(), matches(r'^Action "throws" took .+'));
     });
   });
+
+  group('Memory allocations', () {
+    ObjectEvent? dispatchedEvent;
+    final Object object = List<int>.filled(1, 0);
+
+    void listener(ObjectEvent event) {
+      expect(dispatchedEvent, null);
+      dispatchedEvent = event;
+    }
+
+    setUp(() {
+      dispatchedEvent = null;
+      FlutterMemoryAllocations.instance.addListener(listener);
+    });
+
+    tearDown(() {
+      FlutterMemoryAllocations.instance.removeListener(listener);
+    });
+
+    test('debugMaybeDispatchObjectCreated', () async {
+      debugMaybeDispatchObjectCreated('library', 'class', object);
+
+      if (kFlutterMemoryAllocationsEnabled) {
+        final ObjectEvent? theEvent = dispatchedEvent;
+
+        if (theEvent is! ObjectCreated) {
+          fail('Expected ObjectCreated event');
+        }
+
+        expect(theEvent.object, object);
+        expect(theEvent.library, 'library');
+        expect(theEvent.className, 'class');
+      } else {
+        expect(dispatchedEvent, isNull);
+      }
+    });
+
+    test('debugMaybeDispatchObjectDisposed', () async {
+      debugMaybeDispatchObjectDisposed(object);
+
+      if (kFlutterMemoryAllocationsEnabled) {
+        final ObjectEvent? theEvent = dispatchedEvent;
+
+        if (theEvent is! ObjectDisposed) {
+          fail('Expected ObjectDisposed event');
+        }
+
+        expect(theEvent.object, object);
+      } else {
+        expect(dispatchedEvent, isNull);
+      }
+    });
+  });
 }