Instrument Image and Picture for leak tracking.

lib/ui/painting.dart

@@ -1649,12 +1649,27 @@ class Image {
       return true;
     }());
     _image._handles.add(this);
+    onCreate?.call(this);
   }
 
   // C++ unit tests access this.
   @pragma('vm:entry-point')
   final _Image _image;
 
+  /// A callback that is invoked to report an object creation.
+  ///
+  /// It's preferred to use [MemoryAllocations] in flutter/foundation.dart
+  /// than to use [onCreate] directly because [MemoryAllocations]
+  /// allows multiple callbacks.
+  static void Function(Image)? onCreate;
+
+  /// A callback that is invoked to report the object disposal.
+  ///
+  /// It's preferred to use [MemoryAllocations] in flutter/foundation.dart
+  /// than to use [onDispose] directly because [MemoryAllocations]
+  /// allows multiple callbacks.
+  static void Function(Image)? onDispose;
+
   StackTrace? _debugStack;
 
   /// The number of image pixels along the image's horizontal axis.
@@ -1675,6 +1690,7 @@ class Image {
   /// useful when trying to determine what parts of the program are keeping an
   /// image resident in memory.
   void dispose() {
+    onDispose?.call(this);
     assert(!_disposed && !_image._disposed);
     assert(_image._handles.contains(this));
     _disposed = true;
@@ -5591,7 +5607,21 @@ class Picture extends NativeFieldWrapperClass1 {
   ///
   /// To create a [Picture], use a [PictureRecorder].
   @pragma('vm:entry-point')
-  Picture._();
+  Picture._() { onCreate?.call(this); }
+
+  /// A callback that is invoked to report an object creation.
+  ///
+  /// It's preferred to use [MemoryAllocations] in flutter/foundation.dart
+  /// than to use [onCreate] directly because [MemoryAllocations]
+  /// allows multiple callbacks.
+  static void Function(Picture)? onCreate;
+
+  /// A callback that is invoked to report the object disposal.
+  ///
+  /// It's preferred to use [MemoryAllocations] in flutter/foundation.dart
+  /// than to use [onDispose] directly because [MemoryAllocations]
+  /// allows multiple callbacks.
+  static void Function(Picture)? onDispose;
 
   /// Creates an image from this picture.
   ///
@@ -5656,6 +5686,7 @@ class Picture extends NativeFieldWrapperClass1 {
       _disposed = true;
       return true;
     }());
+    onDispose?.call(this);
     _dispose();
   }
 

lib/web_ui/lib/canvas.dart

@@ -154,9 +154,12 @@ abstract class Canvas {
 }
 
 abstract class Picture {
+  Picture() { onCreate?.call(this); }
+  static void Function(Picture)? onCreate;
+  static void Function(Picture)? onDispose;
   Future<Image> toImage(int width, int height);
   Image toImageSync(int width, int height);
-  void dispose();
+  void dispose() { onDispose?.call(this); }
   bool get debugDisposed;
   int get approximateBytesUsed;
 }

lib/web_ui/lib/painting.dart

@@ -332,6 +332,9 @@ abstract class Gradient extends Shader {
 }
 
 abstract class Image {
+  static void Function(Image)? onCreate;
+  static void Function(Image)? onDispose;
+
   int get width;
   int get height;
   Future<ByteData?> toByteData({ImageByteFormat format = ImageByteFormat.rawRgba});

lib/web_ui/lib/src/engine/canvaskit/image.dart

@@ -149,9 +149,7 @@ Future<Uint8List> fetchImage(
 /// A [ui.Image] backed by an `SkImage` from Skia.
 class CkImage implements ui.Image, StackTraceDebugger {
   CkImage(SkImage skImage, { this.videoFrame }) {
-    if (assertionsEnabled) {
-      _debugStackTrace = StackTrace.current;
-    }
+    _init();
     if (browserSupportsFinalizationRegistry) {
       box = SkiaObjectBox<CkImage, SkImage>(this, skImage);
     } else {
@@ -200,10 +198,15 @@ class CkImage implements ui.Image, StackTraceDebugger {
   }
 
   CkImage.cloneOf(this.box) {
+    _init();
+    box.ref(this);
+  }
+
+  void _init() {
     if (assertionsEnabled) {
       _debugStackTrace = StackTrace.current;
     }
-    box.ref(this);
+    ui.Image.onCreate?.call(this);
   }
 
   @override
@@ -237,6 +240,7 @@ class CkImage implements ui.Image, StackTraceDebugger {
 
   @override
   void dispose() {
+    ui.Image.onDispose?.call(this);
     assert(
       !_disposed,
       'Cannot dispose an image that has already been disposed.',

lib/web_ui/lib/src/engine/embedder.dart

@@ -419,9 +419,7 @@ class FlutterViewEmbedder {
   /// Called immediately after browser window language change.
   void _languageDidChange(DomEvent event) {
     EnginePlatformDispatcher.instance.updateLocales();
-    if (ui.window.onLocaleChanged != null) {
-      ui.window.onLocaleChanged!();
-    }
+    ui.window.onLocaleChanged?.call();
   }
 
   static const String orientationLockTypeAny = 'any';

lib/web_ui/lib/src/engine/html_image_codec.dart

@@ -140,14 +140,17 @@ class SingleFrameInfo implements ui.FrameInfo {
 }
 
 class HtmlImage implements ui.Image {
-  HtmlImage(this.imgElement, this.width, this.height);
+  HtmlImage(this.imgElement, this.width, this.height) {
+    ui.Image.onCreate?.call(this);
+  }
 
   final DomHTMLImageElement imgElement;
   bool _requiresClone = false;
 
   bool _disposed = false;
   @override
   void dispose() {
+    ui.Image.onDispose?.call(this);
     // Do nothing. The codec that owns this image should take care of
     // releasing the object url.
     if (assertionsEnabled) {

lib/web_ui/test/engine/image/image_test.dart

@@ -0,0 +1,60 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+import 'package:ui/ui.dart';
+
+void main() {
+  test('Image constructor invokes onCreate once', () async {
+    int onCreateInvokedCount = 0;
+    Image? createdImage;
+    Image.onCreate = (Image image) {
+      onCreateInvokedCount++;
+      createdImage = image;
+    };
+
+    final Image image1 = await _createImage();
+
+    expect(onCreateInvokedCount, 1);
+    expect(createdImage, image1);
+
+    final Image image2 = await _createImage();
+
+    expect(onCreateInvokedCount, 2);
+    expect(createdImage, image2);
+    Image.onCreate = null;
+  });
+
+  test('dispose() invokes onDispose once', () async {
+    int onDisposeInvokedCount = 0;
+    Image? disposedImage;
+    Image.onDispose = (Image image) {
+      onDisposeInvokedCount++;
+      disposedImage = image;
+    };
+
+    final Image image1 = await _createImage()..dispose();
+
+    expect(onDisposeInvokedCount, 1);
+    expect(disposedImage, image1);
+
+    final Image image2 = await _createImage()..dispose();
+
+    expect(onDisposeInvokedCount, 2);
+    expect(disposedImage, image2);
+
+    Image.onDispose = null;
+  });
+}
+
+
+Future<Image> _createImage() async => _createPicture().toImage(10, 10);
+
+Picture _createPicture() {
+  final PictureRecorder recorder = PictureRecorder();
+  final Canvas canvas = Canvas(recorder);
+  const Rect rect = Rect.fromLTWH(0.0, 0.0, 100.0, 100.0);
+  canvas.clipRect(rect);
+  return recorder.endRecording();
+}

lib/web_ui/test/engine/picture_test.dart

@@ -0,0 +1,57 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+import 'package:ui/ui.dart';
+
+void main() {
+  test('Picture constructor invokes onCreate once', () async {
+    int onCreateInvokedCount = 0;
+    Picture? createdPicture;
+    Picture.onCreate = (Picture picture) {
+      onCreateInvokedCount++;
+      createdPicture = picture;
+    };
+
+    final Picture picture1 = _createPicture();
+
+    expect(onCreateInvokedCount, 1);
+    expect(createdPicture, picture1);
+
+    final Picture picture2 = _createPicture();
+
+    expect(onCreateInvokedCount, 2);
+    expect(createdPicture, picture2);
+    Picture.onCreate = null;
+  });
+
+  test('dispose() invokes onDispose once', () async {
+    int onDisposeInvokedCount = 0;
+    Picture? disposedPicture;
+    Picture.onDispose = (Picture picture) {
+      onDisposeInvokedCount++;
+      disposedPicture = picture;
+    };
+
+    final Picture picture1 = _createPicture()..dispose();
+
+    expect(onDisposeInvokedCount, 1);
+    expect(disposedPicture, picture1);
+
+    final Picture picture2 = _createPicture()..dispose();
+
+    expect(onDisposeInvokedCount, 2);
+    expect(disposedPicture, picture2);
+
+    Picture.onDispose = null;
+  });
+}
+
+Picture _createPicture() {
+  final PictureRecorder recorder = PictureRecorder();
+  final Canvas canvas = Canvas(recorder);
+  const Rect rect = Rect.fromLTWH(0.0, 0.0, 100.0, 100.0);
+  canvas.clipRect(rect);
+  return recorder.endRecording();
+}

testing/dart/BUILD.gn

@@ -20,6 +20,7 @@ tests = [
   "gradient_test.dart",
   "http_allow_http_connections_test.dart",
   "http_disallow_http_connections_test.dart",
+  "image_test.dart",
   "image_descriptor_test.dart",
   "image_dispose_test.dart",
   "image_filter_test.dart",
@@ -33,6 +34,7 @@ tests = [
   "paragraph_builder_test.dart",
   "paragraph_test.dart",
   "path_test.dart",
+  "picture_test.dart",
   "platform_view_test.dart",
   "plugin_utilities_test.dart",
   "semantics_test.dart",

testing/dart/image_dispose_test.dart

@@ -17,7 +17,7 @@ void main() {
   }());
 
   test('Handles are distinct', () async {
-    final Uint8List bytes = await readFile('2x2.png');
+    final Uint8List bytes = await _readFile('2x2.png');
     final Codec codec = await instantiateImageCodec(bytes);
     final FrameInfo frame = await codec.getNextFrame();
 
@@ -36,7 +36,7 @@ void main() {
   });
 
   test('Canvas can paint image from handle and byte data from handle', () async {
-    final Uint8List bytes = await readFile('2x2.png');
+    final Uint8List bytes = await _readFile('2x2.png');
     final Codec codec = await instantiateImageCodec(bytes);
     final FrameInfo frame = await codec.getNextFrame();
 
@@ -66,7 +66,7 @@ void main() {
   });
 
   test('Records stack traces', () async {
-    final Uint8List bytes = await readFile('2x2.png');
+    final Uint8List bytes = await _readFile('2x2.png');
     final Codec codec = await instantiateImageCodec(bytes);
     final FrameInfo frame = await codec.getNextFrame();
 
@@ -92,7 +92,7 @@ void main() {
   }, skip: !assertsEnabled);
 
   test('Clones can be compared', () async {
-    final Uint8List bytes = await readFile('2x2.png');
+    final Uint8List bytes = await _readFile('2x2.png');
     final Codec codec = await instantiateImageCodec(bytes);
     final FrameInfo frame = await codec.getNextFrame();
 
@@ -115,7 +115,7 @@ void main() {
   });
 
   test('debugDisposed works', () async {
-    final Uint8List bytes = await readFile('2x2.png');
+    final Uint8List bytes = await _readFile('2x2.png');
     final Codec codec = await instantiateImageCodec(bytes);
     final FrameInfo frame = await codec.getNextFrame();
 
@@ -132,9 +132,40 @@ void main() {
       expect(() => frame.image.debugDisposed, throwsStateError);
     }
   });
+
+  test('dispose() invokes onDispose once', () async {
+    int onDisposeInvokedCount = 0;
+    Image? disposedImage;
+    Image.onDispose = (Image image) {
+      onDisposeInvokedCount++;
+      disposedImage = image;
+    };
+
+    final Image image1 = await _createImage()..dispose();
+
+    expect(onDisposeInvokedCount, 1);
+    expect(disposedImage, image1);
+
+    final Image image2 = await _createImage()..dispose();
+
+    expect(onDisposeInvokedCount, 2);
+    expect(disposedImage, image2);
+
+    Image.onDispose = null;
+  });
+}
+
+Future<Image> _createImage() async => _createPicture().toImage(10, 10);
+
+Picture _createPicture() {
+  final PictureRecorder recorder = PictureRecorder();
+  final Canvas canvas = Canvas(recorder);
+  const Rect rect = Rect.fromLTWH(0.0, 0.0, 100.0, 100.0);
+  canvas.clipRect(rect);
+  return recorder.endRecording();
 }
 
-Future<Uint8List> readFile(String fileName) async {
+Future<Uint8List> _readFile(String fileName) async {
   final File file = File(path.join(
     'flutter',
     'testing',