Dispose of images after using them (#66688)

* Dispose of images after using them
Adds ImageInfo.clone, ImageInfo.dispose, and ImageInfo.isCloneOf.
Makes all stateful holders of ui.Image objects properly clone and dispose of them.
Behavior change for ImageStreamCompleter: Removing the last listener after registering at least one listener results in the object being disposed, and new listeners cannot be added, unless a keepAlive handle is created.
Makes all non-stateful holders of ui.Image (i.e. paintImage and RawImage) assert that whoever gave the image to them has not disposed it on them.

packages/flutter/lib/src/painting/decoration_image.dart

@@ -295,6 +295,11 @@ class DecorationImagePainter {
   void _handleImage(ImageInfo value, bool synchronousCall) {
     if (_image == value)
       return;
+    if (_image != null && _image!.isCloneOf(value)) {
+      value.dispose();
+      return;
+    }
+    _image?.dispose();
     _image = value;
     assert(_onChanged != null);
     if (!synchronousCall)
@@ -312,6 +317,8 @@ class DecorationImagePainter {
       _handleImage,
       onError: _details.onError,
     ));
+    _image?.dispose();
+    _image = null;
   }
 
   @override
@@ -429,6 +436,12 @@ void paintImage({
   assert(repeat != null);
   assert(flipHorizontally != null);
   assert(isAntiAlias != null);
+  assert(
+    image.debugGetOpenHandleStackTraces()?.isNotEmpty ?? true,
+    'Cannot paint an image that is disposed.\n'
+    'The caller of paintImage is expected to wait to dispose the image until '
+    'after painting has completed.'
+  );
   if (rect.isEmpty)
     return;
   Size outputSize = rect.size;

packages/flutter/lib/src/painting/image_cache.dart

@@ -6,6 +6,7 @@ import 'dart:developer';
 import 'dart:ui' show hashValues;
 
 import 'package:flutter/foundation.dart';
+import 'package:flutter/scheduler.dart';
 
 import 'image_stream.dart';
 
@@ -238,7 +239,7 @@ class ImageCache {
       // In such a case, we need to make sure subsequent calls to
       // putIfAbsent don't return this image that may never complete.
       final _LiveImage? image = _liveImages.remove(key);
-      image?.removeListener();
+      image?.dispose();
     }
     final _PendingImage? pendingImage = _pendingImages.remove(key);
     if (pendingImage != null) {
@@ -259,6 +260,7 @@ class ImageCache {
         });
       }
       _currentSizeBytes -= image.sizeBytes!;
+      image.dispose();
       return true;
     }
     if (!kReleaseMode) {
@@ -276,23 +278,30 @@ class ImageCache {
   /// [maximumSize] and [maximumSizeBytes].
   void _touch(Object key, _CachedImage image, TimelineTask? timelineTask) {
     assert(timelineTask != null);
-    if (image.sizeBytes != null && image.sizeBytes! <= maximumSizeBytes) {
+    if (image.sizeBytes != null && image.sizeBytes! <= maximumSizeBytes && maximumSize > 0) {
       _currentSizeBytes += image.sizeBytes!;
       _cache[key] = image;
       _checkCacheSize(timelineTask);
+    } else {
+      image.dispose();
     }
   }
 
-  void _trackLiveImage(Object key, _LiveImage image) {
+  void _trackLiveImage(Object key, ImageStreamCompleter completer, int? sizeBytes) {
     // Avoid adding unnecessary callbacks to the completer.
     _liveImages.putIfAbsent(key, () {
       // Even if no callers to ImageProvider.resolve have listened to the stream,
       // the cache is listening to the stream and will remove itself once the
       // image completes to move it from pending to keepAlive.
-      // Even if the cache size is 0, we still add this listener.
-      image.completer.addOnLastListenerRemovedCallback(image.handleRemove);
-      return image;
-    }).sizeBytes ??= image.sizeBytes;
+      // Even if the cache size is 0, we still add this tracker, which will add
+      // a keep alive handle to the stream.
+      return _LiveImage(
+        completer,
+        () {
+          _liveImages.remove(key);
+        },
+      );
+    }).sizeBytes ??= sizeBytes;
   }
 
   /// Returns the previously cached [ImageStream] for the given key, if available;
@@ -337,14 +346,25 @@ class ImageCache {
       }
       // The image might have been keptAlive but had no listeners (so not live).
       // Make sure the cache starts tracking it as live again.
-      _trackLiveImage(key, _LiveImage(image.completer, image.sizeBytes, () => _liveImages.remove(key)));
+      _trackLiveImage(
+        key,
+        image.completer,
+        image.sizeBytes,
+      );
       _cache[key] = image;
       return image.completer;
     }
 
-    final _CachedImage? liveImage = _liveImages[key];
+    final _LiveImage? liveImage = _liveImages[key];
     if (liveImage != null) {
-      _touch(key, liveImage, timelineTask);
+      _touch(
+        key,
+        _CachedImage(
+          liveImage.completer,
+          sizeBytes: liveImage.sizeBytes,
+        ),
+        timelineTask,
+      );
       if (!kReleaseMode) {
         timelineTask!.finish(arguments: <String, dynamic>{'result': 'keepAlive'});
       }
@@ -353,7 +373,7 @@ class ImageCache {
 
     try {
       result = loader();
-      _trackLiveImage(key, _LiveImage(result, null, () => _liveImages.remove(key)));
+      _trackLiveImage(key, result, null);
     } catch (error, stackTrace) {
       if (!kReleaseMode) {
         timelineTask!.finish(arguments: <String, dynamic>{
@@ -384,33 +404,33 @@ class ImageCache {
     // If the cache is disabled, this variable will be set.
     _PendingImage? untrackedPendingImage;
     void listener(ImageInfo? info, bool syncCall) {
-      // Images that fail to load don't contribute to cache size.
-      final int imageSize = info == null || info.image == null ? 0 : info.image.height * info.image.width * 4;
-
-      final _CachedImage image = _CachedImage(result!, imageSize);
-
-      _trackLiveImage(
-        key,
-        _LiveImage(
-          result,
-          imageSize,
-          () => _liveImages.remove(key),
-        ),
+      int? sizeBytes;
+      if (info != null) {
+        sizeBytes = info.image.height * info.image.width * 4;
+        info.dispose();
+      }
+      final _CachedImage image = _CachedImage(
+        result!,
+        sizeBytes: sizeBytes,
       );
 
-      final _PendingImage? pendingImage = untrackedPendingImage ?? _pendingImages.remove(key);
-      if (pendingImage != null) {
-        pendingImage.removeListener();
-      }
+      _trackLiveImage(key, result, sizeBytes);
+
       // Only touch if the cache was enabled when resolve was initially called.
       if (untrackedPendingImage == null) {
         _touch(key, image, listenerTask);
+      } else {
+        image.dispose();
       }
 
+      final _PendingImage? pendingImage = untrackedPendingImage ?? _pendingImages.remove(key);
+      if (pendingImage != null) {
+        pendingImage.removeListener();
+      }
       if (!kReleaseMode && !listenedOnce) {
         listenerTask!.finish(arguments: <String, dynamic>{
           'syncCall': syncCall,
-          'sizeInBytes': imageSize,
+          'sizeInBytes': sizeBytes,
         });
         timelineTask!.finish(arguments: <String, dynamic>{
           'currentSizeBytes': currentSizeBytes,
@@ -469,7 +489,7 @@ class ImageCache {
   /// that are also being held by at least one other object.
   void clearLiveImages() {
     for (final _LiveImage image in _liveImages.values) {
-      image.removeListener();
+      image.dispose();
     }
     _liveImages.clear();
   }
@@ -489,6 +509,7 @@ class ImageCache {
       final Object key = _cache.keys.first;
       final _CachedImage image = _cache[key]!;
       _currentSizeBytes -= image.sizeBytes!;
+      image.dispose();
       _cache.remove(key);
       if (!kReleaseMode) {
         finishArgs['evictedKeys'].add(key.toString());
@@ -576,22 +597,59 @@ class ImageCacheStatus {
   String toString() => '${objectRuntimeType(this, 'ImageCacheStatus')}(pending: $pending, live: $live, keepAlive: $keepAlive)';
 }
 
-class _CachedImage {
-  _CachedImage(this.completer, this.sizeBytes);
+/// Base class for [_CachedImage] and [_LiveImage].
+///
+/// Exists primarily so that a [_LiveImage] cannot be added to the
+/// [ImageCache._cache].
+abstract class _CachedImageBase {
+  _CachedImageBase(
+    this.completer, {
+    this.sizeBytes,
+  }) : assert(completer != null),
+       handle = completer.keepAlive();
 
   final ImageStreamCompleter completer;
   int? sizeBytes;
+  ImageStreamCompleterHandle? handle;
+
+  @mustCallSuper
+  void dispose() {
+    assert(handle != null);
+    // Give any interested parties a chance to listen to the stream before we
+    // potentially dispose it.
+    SchedulerBinding.instance!.addPostFrameCallback((Duration timeStamp) {
+      assert(handle != null);
+      handle?.dispose();
+      handle = null;
+    });
+  }
 }
 
-class _LiveImage extends _CachedImage {
-  _LiveImage(ImageStreamCompleter completer, int? sizeBytes, this.handleRemove)
-      : super(completer, sizeBytes);
+class _CachedImage extends _CachedImageBase {
+  _CachedImage(ImageStreamCompleter completer, {int? sizeBytes})
+      : super(completer, sizeBytes: sizeBytes);
+}
 
-  final VoidCallback handleRemove;
+class _LiveImage extends _CachedImageBase {
+  _LiveImage(ImageStreamCompleter completer, VoidCallback handleRemove, {int? sizeBytes})
+      : super(completer, sizeBytes: sizeBytes) {
+    _handleRemove = () {
+      handleRemove();
+      dispose();
+    };
+    completer.addOnLastListenerRemovedCallback(_handleRemove);
+  }
 
-  void removeListener() {
-    completer.removeOnLastListenerRemovedCallback(handleRemove);
+  late VoidCallback _handleRemove;
+
+  @override
+  void dispose() {
+    completer.removeOnLastListenerRemovedCallback(_handleRemove);
+    super.dispose();
   }
+
+  @override
+  String toString() => describeIdentity(this);
 }
 
 class _PendingImage {

packages/flutter/lib/src/painting/image_provider.dart

@@ -284,6 +284,7 @@ typedef DecoderCallback = Future<ui.Codec> Function(Uint8List bytes, {int? cache
 ///   void _updateImage(ImageInfo imageInfo, bool synchronousCall) {
 ///     setState(() {
 ///       // Trigger a build whenever the image changes.
+///       _imageInfo?.image?.dispose();
 ///       _imageInfo = imageInfo;
 ///     });
 ///   }
@@ -291,6 +292,8 @@ typedef DecoderCallback = Future<ui.Codec> Function(Uint8List bytes, {int? cache
 ///   @override
 ///   void dispose() {
 ///     _imageStream.removeListener(ImageStreamListener(_updateImage));
+///     _imageInfo?.image?.dispose();
+///     _imageInfo = null;
 ///     super.dispose();
 ///   }
 ///

packages/flutter/lib/src/rendering/image.dart

@@ -85,8 +85,16 @@ class RenderImage extends RenderBox {
   ui.Image? get image => _image;
   ui.Image? _image;
   set image(ui.Image? value) {
-    if (value == _image)
+    if (value == _image) {
       return;
+    }
+    // If we get a clone of our image, it's the same underlying native data -
+    // dispose of the new clone and return early.
+    if (value != null && _image != null && value.isCloneOf(_image!)) {
+      value.dispose();
+      return;
+    }
+    _image?.dispose();
     _image = value;
     markNeedsPaint();
     if (_width == null || _height == null)

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

@@ -5363,6 +5363,10 @@ class RichText extends MultiChildRenderObjectWidget {
 /// The image is painted using [paintImage], which describes the meanings of the
 /// various fields on this class in more detail.
 ///
+/// The [image] is not disposed of by this widget. Creators of the widget are
+/// expected to call [Image.dispose] on the [image] once the [RawImage] is no
+/// longer buildable.
+///
 /// This widget is rarely used directly. Instead, consider using [Image].
 class RawImage extends LeafRenderObjectWidget {
   /// Creates a widget that displays an image.
@@ -5394,6 +5398,10 @@ class RawImage extends LeafRenderObjectWidget {
        super(key: key);
 
   /// The image to display.
+  ///
+  /// Since a [RawImage] is stateless, it does not ever dispose this image.
+  /// Creators of a [RawImage] are expected to call [Image.dispose] on this
+  /// image handle when the [RawImage] will no longer be needed.
   final ui.Image? image;
 
   /// A string identifying the source of the image.
@@ -5516,8 +5524,13 @@ class RawImage extends LeafRenderObjectWidget {
   @override
   RenderImage createRenderObject(BuildContext context) {
     assert((!matchTextDirection && alignment is Alignment) || debugCheckHasDirectionality(context));
+    assert(
+      image?.debugGetOpenHandleStackTraces()?.isNotEmpty ?? true,
+      'Creator of a RawImage disposed of the image when the RawImage still '
+      'needed it.'
+    );
     return RenderImage(
-      image: image,
+      image: image?.clone(),
       debugImageLabel: debugImageLabel,
       width: width,
       height: height,
@@ -5538,8 +5551,13 @@ class RawImage extends LeafRenderObjectWidget {
 
   @override
   void updateRenderObject(BuildContext context, RenderImage renderObject) {
+    assert(
+      image?.debugGetOpenHandleStackTraces()?.isNotEmpty ?? true,
+      'Creator of a RawImage disposed of the image when the RawImage still '
+      'needed it.'
+    );
     renderObject
-      ..image = image
+      ..image = image?.clone()
       ..debugImageLabel = debugImageLabel
       ..width = width
       ..height = height
@@ -5556,6 +5574,12 @@ class RawImage extends LeafRenderObjectWidget {
       ..filterQuality = filterQuality;
   }
 
+  @override
+  void didUnmountRenderObject(RenderImage renderObject) {
+    // Have the render object dispose its image handle.
+    renderObject.image = null;
+  }
+
   @override
   void debugFillProperties(DiagnosticPropertiesBuilder properties) {
     super.debugFillProperties(properties);

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

@@ -1084,6 +1084,7 @@ class _ImageState extends State<Image> with WidgetsBindingObserver {
   late DisposableBuildContext<State<Image>> _scrollAwareContext;
   Object? _lastException;
   StackTrace? _lastStack;
+  ImageStreamCompleterHandle? _completerHandle;
 
   @override
   void initState() {
@@ -1097,7 +1098,9 @@ class _ImageState extends State<Image> with WidgetsBindingObserver {
     assert(_imageStream != null);
     WidgetsBinding.instance!.removeObserver(this);
     _stopListeningToStream();
+    _completerHandle?.dispose();
     _scrollAwareContext.dispose();
+    _replaceImage(info: null);
     super.dispose();
   }
 
@@ -1109,7 +1112,7 @@ class _ImageState extends State<Image> with WidgetsBindingObserver {
     if (TickerMode.of(context))
       _listenToStream();
     else
-      _stopListeningToStream();
+      _stopListeningToStream(keepStreamAlive: true);
 
     super.didChangeDependencies();
   }
@@ -1119,8 +1122,9 @@ class _ImageState extends State<Image> with WidgetsBindingObserver {
     super.didUpdateWidget(oldWidget);
     if (_isListeningToStream &&
         (widget.loadingBuilder == null) != (oldWidget.loadingBuilder == null)) {
-      _imageStream!.removeListener(_getListener());
+      final ImageStreamListener oldListener = _getListener();
       _imageStream!.addListener(_getListener(recreateListener: true));
+      _imageStream!.removeListener(oldListener);
     }
     if (widget.image != oldWidget.image)
       _resolveImage();
@@ -1182,7 +1186,7 @@ class _ImageState extends State<Image> with WidgetsBindingObserver {
 
   void _handleImageFrame(ImageInfo imageInfo, bool synchronousCall) {
     setState(() {
-      _imageInfo = imageInfo;
+      _replaceImage(info: imageInfo);
       _loadingProgress = null;
       _lastException = null;
       _lastStack = null;
@@ -1200,6 +1204,11 @@ class _ImageState extends State<Image> with WidgetsBindingObserver {
     });
   }
 
+  void _replaceImage({required ImageInfo? info}) {
+    _imageInfo?.dispose();
+    _imageInfo = info;
+  }
+
   // Updates _imageStream to newStream, and moves the stream listener
   // registration from the old stream to the new stream (if a listener was
   // registered).
@@ -1211,7 +1220,7 @@ class _ImageState extends State<Image> with WidgetsBindingObserver {
       _imageStream!.removeListener(_getListener());
 
     if (!widget.gaplessPlayback)
-      setState(() { _imageInfo = null; });
+      setState(() { _replaceImage(info: null); });
 
     setState(() {
       _loadingProgress = null;
@@ -1227,13 +1236,29 @@ class _ImageState extends State<Image> with WidgetsBindingObserver {
   void _listenToStream() {
     if (_isListeningToStream)
       return;
+
     _imageStream!.addListener(_getListener());
+    _completerHandle?.dispose();
+    _completerHandle = null;
+
     _isListeningToStream = true;
   }
 
-  void _stopListeningToStream() {
+  /// Stops listening to the image stream, if this state object has attached a
+  /// listener.
+  ///
+  /// If the listener from this state is the last listener on the stream, the
+  /// stream will be disposed. To keep the stream alive, set `keepStreamAlive`
+  /// to true, which will add a passive listener on the stream and is compatible
+  /// with the [TickerMode] being off.
+  void _stopListeningToStream({bool keepStreamAlive = false}) {
     if (!_isListeningToStream)
       return;
+
+    if (keepStreamAlive && _completerHandle == null && _imageStream?.completer != null) {
+      _completerHandle = _imageStream!.completer!.keepAlive();
+    }
+
     _imageStream!.removeListener(_getListener());
     _isListeningToStream = false;
   }
@@ -1246,6 +1271,10 @@ class _ImageState extends State<Image> with WidgetsBindingObserver {
     }
 
     Widget result = RawImage(
+      // Do not clone the image, because RawImage is a stateless wrapper.
+      // The image will be disposed by this state object when it is not needed
+      // anymore, such as when it is unmounted or when the image stream pushes
+      // a new image.
       image: _imageInfo?.image,
       debugImageLabel: _imageInfo?.debugLabel,
       width: widget.width,

packages/flutter/test/painting/decoration_test.dart

@@ -6,6 +6,7 @@
 
 @TestOn('!chrome')
 import 'dart:async';
+import 'dart:typed_data';
 import 'dart:ui' as ui show Image, ColorFilter;
 
 import 'package:flutter/foundation.dart';
@@ -13,6 +14,7 @@ import 'package:flutter/painting.dart';
 import 'package:fake_async/fake_async.dart';
 
 import '../flutter_test_alternative.dart';
+import '../image_data.dart';
 import '../painting/mocks_for_image_cache.dart';
 import '../rendering/rendering_tester.dart';
 
@@ -62,6 +64,10 @@ class SynchronousErrorTestImageProvider extends ImageProvider<int> {
 }
 
 class AsyncTestImageProvider extends ImageProvider<int> {
+  AsyncTestImageProvider(this.image);
+
+  final ui.Image image;
+
   @override
   Future<int> obtainKey(ImageConfiguration configuration) {
     return Future<int>.value(2);
@@ -70,7 +76,7 @@ class AsyncTestImageProvider extends ImageProvider<int> {
   @override
   ImageStreamCompleter load(int key, DecoderCallback decode) {
     return OneFrameImageStreamCompleter(
-      Future<ImageInfo>.value(TestImageInfo(key))
+      Future<ImageInfo>.value(TestImageInfo(key, image: image))
     );
   }
 }
@@ -100,6 +106,31 @@ class DelayedImageProvider extends ImageProvider<DelayedImageProvider> {
   String toString() => '${describeIdentity(this)}()';
 }
 
+class MultiFrameImageProvider extends ImageProvider<MultiFrameImageProvider> {
+  MultiFrameImageProvider(this.completer);
+
+  final MultiImageCompleter completer;
+
+  @override
+  Future<MultiFrameImageProvider> obtainKey(ImageConfiguration configuration) {
+    return SynchronousFuture<MultiFrameImageProvider>(this);
+  }
+
+  @override
+  ImageStreamCompleter load(MultiFrameImageProvider key, DecoderCallback decode) {
+    return completer;
+  }
+
+  @override
+  String toString() => '${describeIdentity(this)}()';
+}
+
+class MultiImageCompleter extends ImageStreamCompleter {
+  void testSetImage(ImageInfo info) {
+    setImage(info);
+  }
+}
+
 void main() {
   TestRenderingFlutterBinding(); // initializes the imageCache
 
@@ -151,9 +182,10 @@ void main() {
     expect(onChangedCalled, equals(false));
   });
 
-  test('BoxDecorationImageListenerAsync', () {
+  test('BoxDecorationImageListenerAsync', () async {
+    final ui.Image image = await createTestImage(width: 10, height: 10);
     FakeAsync().run((FakeAsync async) {
-      final ImageProvider imageProvider = AsyncTestImageProvider();
+      final ImageProvider imageProvider = AsyncTestImageProvider(image);
       final DecorationImage backgroundImage = DecorationImage(image: imageProvider);
 
       final BoxDecoration boxDecoration = BoxDecoration(image: backgroundImage);
@@ -173,6 +205,42 @@ void main() {
     });
   });
 
+  test('BoxDecorationImageListener does not change when image is clone', () async {
+    final ui.Image image1 = await createTestImage(width: 10, height: 10, cache: false);
+    final ui.Image image2 = await createTestImage(width: 10, height: 10, cache: false);
+    final MultiImageCompleter completer = MultiImageCompleter();
+    final MultiFrameImageProvider imageProvider = MultiFrameImageProvider(completer);
+    final DecorationImage backgroundImage = DecorationImage(image: imageProvider);
+
+    final BoxDecoration boxDecoration = BoxDecoration(image: backgroundImage);
+    bool onChangedCalled = false;
+    final BoxPainter boxPainter = boxDecoration.createBoxPainter(() {
+      onChangedCalled = true;
+    });
+
+    final TestCanvas canvas = TestCanvas();
+    const ImageConfiguration imageConfiguration = ImageConfiguration(size: Size.zero);
+    boxPainter.paint(canvas, Offset.zero, imageConfiguration);
+
+    // The onChanged callback should be invoked asynchronously.
+    expect(onChangedCalled, equals(false));
+
+    completer.testSetImage(ImageInfo(image: image1.clone()));
+    await null;
+
+    expect(onChangedCalled, equals(true));
+    onChangedCalled = false;
+    completer.testSetImage(ImageInfo(image: image1.clone()));
+    await null;
+
+    expect(onChangedCalled, equals(false));
+
+    completer.testSetImage(ImageInfo(image: image2.clone()));
+    await null;
+
+    expect(onChangedCalled, equals(true));
+  });
+
   // Regression test for https://github.com/flutter/flutter/issues/7289.
   // A reference test would be better.
   test('BoxDecoration backgroundImage clip', () async {
@@ -626,4 +694,30 @@ void main() {
     expect(call.positionalArguments[2].size, const Size(25.0, 25.0));
     expect(call.positionalArguments[2], const Rect.fromLTRB(0.0, 0.0, 25.0, 25.0));
   });
+
+  test('DecorationImagePainter disposes of image when disposed',  () async {
+    final ImageProvider provider = MemoryImage(Uint8List.fromList(kTransparentImage));
+
+    final ImageStream stream = provider.resolve(ImageConfiguration.empty);
+
+    final Completer<ImageInfo> infoCompleter = Completer<ImageInfo>();
+    void _listener(ImageInfo image, bool syncCall) {
+      assert(!infoCompleter.isCompleted);
+      infoCompleter.complete(image);
+    }
+    stream.addListener(ImageStreamListener(_listener));
+
+    final ImageInfo info = await infoCompleter.future;
+    final int baselineRefCount = info.image.debugGetOpenHandleStackTraces().length;
+
+    final DecorationImagePainter painter = DecorationImage(image: provider).createPainter(() {});
+    final Canvas canvas = TestCanvas();
+    painter.paint(canvas, Rect.zero, Path(), ImageConfiguration.empty);
+
+    expect(info.image.debugGetOpenHandleStackTraces().length, baselineRefCount + 1);
+    painter.dispose();
+    expect(info.image.debugGetOpenHandleStackTraces().length, baselineRefCount);
+
+    info.dispose();
+  });
 }

packages/flutter/test/painting/image_cache_test.dart

@@ -6,9 +6,11 @@
 
 import 'dart:ui' as ui;
 
+import 'package:flutter/foundation.dart';
 import 'package:flutter/painting.dart';
-import '../flutter_test_alternative.dart';
+import 'package:flutter/scheduler.dart';
 
+import '../flutter_test_alternative.dart';
 import '../rendering/rendering_tester.dart';
 import 'mocks_for_image_cache.dart';
 
@@ -456,7 +458,6 @@ void main() {
     final TestImageStreamCompleter completer1 = TestImageStreamCompleter()
       ..addListener(listener);
 
-
     imageCache.putIfAbsent(testImage, () => completer1);
     expect(imageCache.statusForKey(testImage).pending, true);
     expect(imageCache.statusForKey(testImage).live, true);
@@ -484,4 +485,88 @@ void main() {
     expect(imageCache.statusForKey(testImage).keepAlive, true);
     expect(imageCache.currentSizeBytes, testImageSize);
   });
+
+  test('Image is obtained and disposed of properly for cache', () async {
+    const int key = 1;
+    final ui.Image testImage = await createTestImage(width: 8, height: 8, cache: false);
+    expect(testImage.debugGetOpenHandleStackTraces().length, 1);
+
+    ImageInfo imageInfo;
+    final ImageStreamListener listener = ImageStreamListener((ImageInfo info, bool syncCall) {
+      imageInfo = info;
+    });
+
+    final TestImageStreamCompleter completer = TestImageStreamCompleter();
+
+    completer.addListener(listener);
+    imageCache.putIfAbsent(key, () => completer);
+
+    expect(testImage.debugGetOpenHandleStackTraces().length, 1);
+
+    // This should cause keepAlive to be set to true.
+    completer.testSetImage(testImage);
+    expect(imageInfo, isNotNull);
+    // +1 ImageStreamCompleter
+    expect(testImage.debugGetOpenHandleStackTraces().length, 2);
+
+    completer.removeListener(listener);
+
+    // Force us to the end of the frame.
+    SchedulerBinding.instance.scheduleFrame();
+    await SchedulerBinding.instance.endOfFrame;
+
+    expect(testImage.debugGetOpenHandleStackTraces().length, 2);
+
+    expect(imageCache.evict(key), true);
+
+    // Force us to the end of the frame.
+    SchedulerBinding.instance.scheduleFrame();
+    await SchedulerBinding.instance.endOfFrame;
+
+    // -1 _CachedImage
+    // -1 ImageStreamCompleter
+    expect(testImage.debugGetOpenHandleStackTraces().length, 1);
+
+    imageInfo.dispose();
+    expect(testImage.debugGetOpenHandleStackTraces().length, 0);
+  }, skip: kIsWeb); // Web does not care about image handles.
+
+  test('Image is obtained and disposed of properly for cache when listener is still active', () async {
+    const int key = 1;
+    final ui.Image testImage = await createTestImage(width: 8, height: 8, cache: false);
+    expect(testImage.debugGetOpenHandleStackTraces().length, 1);
+
+    ImageInfo imageInfo;
+    final ImageStreamListener listener = ImageStreamListener((ImageInfo info, bool syncCall) {
+      imageInfo = info;
+    });
+
+    final TestImageStreamCompleter completer = TestImageStreamCompleter();
+
+    completer.addListener(listener);
+    imageCache.putIfAbsent(key, () => completer);
+
+    expect(testImage.debugGetOpenHandleStackTraces().length, 1);
+
+    // This should cause keepAlive to be set to true.
+    completer.testSetImage(testImage);
+    expect(imageInfo, isNotNull);
+    // Just our imageInfo and the completer.
+    expect(testImage.debugGetOpenHandleStackTraces().length, 2);
+
+    expect(imageCache.evict(key), true);
+
+    // Force us to the end of the frame.
+    SchedulerBinding.instance.scheduleFrame();
+    await SchedulerBinding.instance.endOfFrame;
+
+    // Live image still around since there's still a listener, and the listener
+    // should be holding a handle.
+    expect(testImage.debugGetOpenHandleStackTraces().length, 2);
+    completer.removeListener(listener);
+
+    expect(testImage.debugGetOpenHandleStackTraces().length, 1);
+    imageInfo.dispose();
+    expect(testImage.debugGetOpenHandleStackTraces().length, 0);
+  }, skip: kIsWeb); // Web does not care about open image handles.
 }

packages/flutter/test/painting/image_stream_test.dart

@@ -8,13 +8,12 @@ import 'dart:async';
 import 'dart:ui';
 
 import 'package:flutter/painting.dart';
-import 'package:flutter/scheduler.dart' show timeDilation;
+import 'package:flutter/scheduler.dart' show timeDilation, SchedulerBinding;
 import 'package:flutter_test/flutter_test.dart';
 import 'package:meta/meta.dart';
 
 class FakeFrameInfo implements FrameInfo {
-  FakeFrameInfo(this._duration, this._image);
-
+  const FakeFrameInfo(this._duration, this._image);
 
   final Duration _duration;
   final Image _image;
@@ -24,6 +23,15 @@ class FakeFrameInfo implements FrameInfo {
 
   @override
   Image get image => _image;
+
+  int get imageHandleCount => image.debugGetOpenHandleStackTraces().length;
+
+  FakeFrameInfo clone() {
+    return FakeFrameInfo(
+      _duration,
+      _image.clone(),
+    );
+  }
 }
 
 class MockCodec implements Codec {
@@ -72,7 +80,7 @@ class FakeEventReportingImageStreamCompleter extends ImageStreamCompleter {
 void main() {
   Image image20x10;
   Image image200x100;
-  setUpAll(() async {
+  setUp(() async {
     image20x10 = await createTestImage(width: 20, height: 10);
     image200x100 = await createTestImage(width: 200, height: 100);
   });
@@ -299,7 +307,7 @@ void main() {
     mockCodec.completeNextFrame(frame);
     await tester.idle();
 
-    expect(emittedImages, equals(<ImageInfo>[ImageInfo(image: frame.image)]));
+    expect(emittedImages.every((ImageInfo info) => info.image.isCloneOf(frame.image)), true);
   });
 
   testWidgets('ImageStream emits frames (animated images)', (WidgetTester tester) async {
@@ -329,7 +337,7 @@ void main() {
     expect(emittedImages.length, 0);
 
     await tester.pump();
-    expect(emittedImages, equals(<ImageInfo>[ImageInfo(image: frame1.image)]));
+    expect(emittedImages.single.image.isCloneOf(frame1.image), true);
 
     final FrameInfo frame2 = FakeFrameInfo(const Duration(milliseconds: 400), image200x100);
     mockCodec.completeNextFrame(frame2);
@@ -340,10 +348,8 @@ void main() {
     expect(emittedImages.length, 1);
 
     await tester.pump(const Duration(milliseconds: 100));
-    expect(emittedImages, equals(<ImageInfo>[
-      ImageInfo(image: frame1.image),
-      ImageInfo(image: frame2.image),
-    ]));
+    expect(emittedImages[0].image.isCloneOf(frame1.image), true);
+    expect(emittedImages[1].image.isCloneOf(frame2.image), true);
 
     // Let the pending timer for the next frame to complete so we can cleanly
     // quit the test without pending timers.
@@ -369,24 +375,22 @@ void main() {
     codecCompleter.complete(mockCodec);
     await tester.idle();
 
-    final FrameInfo frame1 = FakeFrameInfo(const Duration(milliseconds: 200), image20x10);
-    final FrameInfo frame2 = FakeFrameInfo(const Duration(milliseconds: 400), image200x100);
+    final FakeFrameInfo frame1 = FakeFrameInfo(const Duration(milliseconds: 200), image20x10);
+    final FakeFrameInfo frame2 = FakeFrameInfo(const Duration(milliseconds: 400), image200x100);
 
-    mockCodec.completeNextFrame(frame1);
+    mockCodec.completeNextFrame(frame1.clone());
     await tester.idle(); // let nextFrameFuture complete
     await tester.pump(); // first animation frame shows on first app frame.
-    mockCodec.completeNextFrame(frame2);
+    mockCodec.completeNextFrame(frame2.clone());
     await tester.idle(); // let nextFrameFuture complete
     await tester.pump(const Duration(milliseconds: 200)); // emit 2nd frame.
-    mockCodec.completeNextFrame(frame1);
+    mockCodec.completeNextFrame(frame1.clone());
     await tester.idle(); // let nextFrameFuture complete
     await tester.pump(const Duration(milliseconds: 400)); // emit 3rd frame
 
-    expect(emittedImages, equals(<ImageInfo>[
-      ImageInfo(image: frame1.image),
-      ImageInfo(image: frame2.image),
-      ImageInfo(image: frame1.image),
-    ]));
+    expect(emittedImages[0].image.isCloneOf(frame1.image), true);
+    expect(emittedImages[1].image.isCloneOf(frame2.image), true);
+    expect(emittedImages[2].image.isCloneOf(frame1.image), true);
 
     // Let the pending timer for the next frame to complete so we can cleanly
     // quit the test without pending timers.
@@ -427,13 +431,11 @@ void main() {
     await tester.idle();
     await tester.pump(const Duration(milliseconds: 400));
 
-    expect(emittedImages, equals(<ImageInfo>[
-      ImageInfo(image: frame1.image),
-      ImageInfo(image: frame2.image),
-    ]));
+    expect(emittedImages[0].image.isCloneOf(frame1.image), true);
+    expect(emittedImages[1].image.isCloneOf(frame2.image), true);
   });
 
-  testWidgets('frames are only decoded when there are active listeners', (WidgetTester tester) async {
+  testWidgets('frames are only decoded when there are listeners', (WidgetTester tester) async {
     final MockCodec mockCodec = MockCodec();
     mockCodec.frameCount = 2;
     mockCodec.repetitionCount = -1;
@@ -446,6 +448,7 @@ void main() {
 
     final ImageListener listener = (ImageInfo image, bool synchronousCall) { };
     imageStream.addListener(ImageStreamListener(listener));
+    final ImageStreamCompleterHandle handle = imageStream.keepAlive();
 
     codecCompleter.complete(mockCodec);
     await tester.idle();
@@ -468,6 +471,8 @@ void main() {
     imageStream.addListener(ImageStreamListener(listener));
     await tester.idle(); // let nextFrameFuture complete
     expect(mockCodec.numFramesAsked, 3);
+
+    handle.dispose();
   });
 
   testWidgets('multiple stream listeners', (WidgetTester tester) async {
@@ -501,8 +506,9 @@ void main() {
     mockCodec.completeNextFrame(frame1);
     await tester.idle(); // let nextFrameFuture complete
     await tester.pump(); // first animation frame shows on first app frame.
-    expect(emittedImages1, equals(<ImageInfo>[ImageInfo(image: frame1.image)]));
-    expect(emittedImages2, equals(<ImageInfo>[ImageInfo(image: frame1.image)]));
+
+    expect(emittedImages1.single.image.isCloneOf(frame1.image), true);
+    expect(emittedImages2.single.image.isCloneOf(frame1.image), true);
 
     mockCodec.completeNextFrame(frame2);
     await tester.idle(); // let nextFrameFuture complete
@@ -510,11 +516,10 @@ void main() {
     imageStream.removeListener(ImageStreamListener(listener1));
 
     await tester.pump(const Duration(milliseconds: 400)); // emit 2nd frame.
-    expect(emittedImages1, equals(<ImageInfo>[ImageInfo(image: frame1.image)]));
-    expect(emittedImages2, equals(<ImageInfo>[
-      ImageInfo(image: frame1.image),
-      ImageInfo(image: frame2.image),
-    ]));
+    expect(emittedImages1.single.image.isCloneOf(frame1.image), true);
+    expect(emittedImages2[0].image.isCloneOf(frame1.image), true);
+    expect(emittedImages2[1].image.isCloneOf(frame2.image), true);
+
   });
 
   testWidgets('timer is canceled when listeners are removed', (WidgetTester tester) async {
@@ -639,8 +644,8 @@ void main() {
 
     await tester.idle(); // let nextFrameFuture complete
 
-    imageStream.removeListener(ImageStreamListener(listener));
     imageStream.addListener(ImageStreamListener(listener));
+    imageStream.removeListener(ImageStreamListener(listener));
 
 
     final FrameInfo frame1 = FakeFrameInfo(const Duration(milliseconds: 200), image20x10);
@@ -684,6 +689,76 @@ void main() {
     compare(onImage1: handleImage, onChunk1: handleChunk, onError1: handleError, onImage2: handleImage, onError2: handleError, areEqual: false);
   });
 
+  testWidgets('Keep alive handles do not drive frames or prevent last listener callbacks', (WidgetTester tester) async {
+    final Image image10x10 = await tester.runAsync(() => createTestImage(width: 10, height: 10));
+    final MockCodec mockCodec = MockCodec();
+    mockCodec.frameCount = 2;
+    mockCodec.repetitionCount = -1;
+    final Completer<Codec> codecCompleter = Completer<Codec>();
+
+    final ImageStreamCompleter imageStream = MultiFrameImageStreamCompleter(
+      codec: codecCompleter.future,
+      scale: 1.0,
+    );
+
+    int onImageCount = 0;
+    final ImageListener activeListener = (ImageInfo image, bool synchronousCall) {
+      onImageCount += 1;
+    };
+    bool lastListenerDropped = false;
+    imageStream.addOnLastListenerRemovedCallback(() {
+      lastListenerDropped = true;
+    });
+
+    expect(lastListenerDropped, false);
+    final ImageStreamCompleterHandle handle = imageStream.keepAlive();
+    expect(lastListenerDropped, false);
+    SchedulerBinding.instance.debugAssertNoTransientCallbacks('Only passive listeners');
+
+    codecCompleter.complete(mockCodec);
+    await tester.idle();
+
+    expect(onImageCount, 0);
+
+    final FakeFrameInfo frame1 = FakeFrameInfo(Duration.zero, image20x10);
+    mockCodec.completeNextFrame(frame1);
+    await tester.idle();
+    SchedulerBinding.instance.debugAssertNoTransientCallbacks('Only passive listeners');
+    await tester.pump();
+    expect(onImageCount, 0);
+
+    imageStream.addListener(ImageStreamListener(activeListener));
+
+    final FakeFrameInfo frame2 = FakeFrameInfo(Duration.zero, image10x10);
+    mockCodec.completeNextFrame(frame2);
+    await tester.idle();
+    expect(SchedulerBinding.instance.transientCallbackCount, 1);
+    await tester.pump();
+
+    expect(onImageCount, 1);
+
+    imageStream.removeListener(ImageStreamListener(activeListener));
+    expect(lastListenerDropped, true);
+
+    mockCodec.completeNextFrame(frame1);
+    await tester.idle();
+    expect(SchedulerBinding.instance.transientCallbackCount, 1);
+    await tester.pump();
+
+    expect(onImageCount, 1);
+
+    SchedulerBinding.instance.debugAssertNoTransientCallbacks('Only passive listeners');
+
+    mockCodec.completeNextFrame(frame2);
+    await tester.idle();
+    SchedulerBinding.instance.debugAssertNoTransientCallbacks('Only passive listeners');
+    await tester.pump();
+
+    expect(onImageCount, 1);
+
+    handle.dispose();
+  });
+
   // TODO(amirh): enable this once WidgetTester supports flushTimers.
   // https://github.com/flutter/flutter/issues/30344
   // testWidgets('remove and add listener before a delayed frame is scheduled', (WidgetTester tester) async {

packages/flutter/test/painting/mocks_for_image_cache.dart

@@ -10,8 +10,10 @@ import 'dart:ui' as ui show Image;
 import 'package:flutter/foundation.dart';
 import 'package:flutter/painting.dart';
 
+// ignore: must_be_immutable
 class TestImageInfo implements ImageInfo {
-  const TestImageInfo(this.value, { this.image, this.scale = 1.0, this.debugLabel });
+  TestImageInfo(this.value, { @required this.image, this.scale = 1.0, this.debugLabel })
+    : assert(image != null);
 
   @override
   final ui.Image image;
@@ -26,6 +28,39 @@ class TestImageInfo implements ImageInfo {
 
   @override
   String toString() => '$runtimeType($value)';
+
+  @override
+  TestImageInfo clone() {
+    return TestImageInfo(value, image: image.clone(), scale: scale, debugLabel: debugLabel);
+  }
+
+  @override
+  bool isCloneOf(ImageInfo other) {
+    assert(other != null);
+    return other.image.isCloneOf(image)
+        && scale == scale
+        && other.debugLabel == debugLabel;
+  }
+
+  @override
+  void dispose() {
+    image.dispose();
+  }
+
+  @override
+  int get hashCode => hashValues(value, image, scale, debugLabel);
+
+  @override
+  bool operator ==(Object other) {
+    if (other.runtimeType != runtimeType)
+      return false;
+    return other is TestImageInfo
+        && other.value == value
+        && other.image.isCloneOf(image)
+        && other.scale == scale
+        && other.debugLabel == debugLabel;
+
+  }
 }
 
 class TestImageProvider extends ImageProvider<int> {
@@ -44,7 +79,7 @@ class TestImageProvider extends ImageProvider<int> {
   @override
   ImageStreamCompleter load(int key, DecoderCallback decode) {
     return OneFrameImageStreamCompleter(
-      SynchronousFuture<ImageInfo>(TestImageInfo(imageValue, image: image))
+      SynchronousFuture<ImageInfo>(TestImageInfo(imageValue, image: image.clone()))
     );
   }
 

packages/flutter/test/rendering/image_test.dart

@@ -176,4 +176,38 @@ Future<void> main() async {
     image.colorBlendMode = BlendMode.color;
     expect(image.colorBlendMode, BlendMode.color);
   });
+
+  test('Render image disposes its image', () async {
+    final ui.Image image = await createTestImage(width: 10, height: 10, cache: false);
+    expect(image.debugGetOpenHandleStackTraces().length, 1);
+
+    final RenderImage renderImage = RenderImage(image: image.clone());
+    expect(image.debugGetOpenHandleStackTraces().length, 2);
+
+    renderImage.image = image.clone();
+    expect(image.debugGetOpenHandleStackTraces().length, 2);
+
+    renderImage.image = null;
+    expect(image.debugGetOpenHandleStackTraces().length, 1);
+
+    image.dispose();
+    expect(image.debugGetOpenHandleStackTraces().length, 0);
+  }, skip: kIsWeb); // Web doesn't track open image handles.
+
+  test('Render image does not dispose its image if setting the same image twice', () async {
+    final ui.Image image = await createTestImage(width: 10, height: 10, cache: false);
+    expect(image.debugGetOpenHandleStackTraces().length, 1);
+
+    final RenderImage renderImage = RenderImage(image: image.clone());
+    expect(image.debugGetOpenHandleStackTraces().length, 2);
+
+    renderImage.image = renderImage.image;
+    expect(image.debugGetOpenHandleStackTraces().length, 2);
+
+    renderImage.image = null;
+    expect(image.debugGetOpenHandleStackTraces().length, 1);
+
+    image.dispose();
+    expect(image.debugGetOpenHandleStackTraces().length, 0);
+  }, skip: kIsWeb); // Web doesn't track open image handles.
 }

packages/flutter/test/rendering/mock_canvas.dart

@@ -1315,7 +1315,7 @@ class _DrawImagePaintPredicate extends _DrawCommandPaintPredicate {
   void verifyArguments(List<dynamic> arguments) {
     super.verifyArguments(arguments);
     final ui.Image imageArgument = arguments[0] as ui.Image;
-    if (image != null && imageArgument != image)
+    if (image != null && !image.isCloneOf(imageArgument))
       throw 'It called $methodName with an image, $imageArgument, which was not exactly the expected image ($image).';
     final Offset pointArgument = arguments[0] as Offset;
     if (x != null && y != null) {
@@ -1359,7 +1359,7 @@ class _DrawImageRectPaintPredicate extends _DrawCommandPaintPredicate {
   void verifyArguments(List<dynamic> arguments) {
     super.verifyArguments(arguments);
     final ui.Image imageArgument = arguments[0] as ui.Image;
-    if (image != null && imageArgument != image)
+    if (image != null && !image.isCloneOf(imageArgument))
       throw 'It called $methodName with an image, $imageArgument, which was not exactly the expected image ($image).';
     final Rect sourceArgument = arguments[1] as Rect;
     if (source != null && sourceArgument != source)

packages/flutter/test/widgets/fade_in_image_test.dart

@@ -132,15 +132,15 @@ Future<void> main() async {
 
       placeholderProvider.complete();
       await tester.pump();
-      expect(findFadeInImage(tester).placeholder.rawImage.image, same(placeholderImage));
+      expect(findFadeInImage(tester).placeholder.rawImage.image.isCloneOf(placeholderImage), true);
       expect(findFadeInImage(tester).target.rawImage.image, null);
 
       imageProvider.complete();
       await tester.pump();
       for (int i = 0; i < 5; i += 1) {
         final FadeInImageParts parts = findFadeInImage(tester);
-        expect(parts.placeholder.rawImage.image, same(placeholderImage));
-        expect(parts.target.rawImage.image, same(targetImage));
+        expect(parts.placeholder.rawImage.image.isCloneOf(placeholderImage), true);
+        expect(parts.target.rawImage.image.isCloneOf(targetImage), true);
         expect(parts.placeholder.opacity, moreOrLessEquals(1 - i / 5));
         expect(parts.target.opacity, 0);
         await tester.pump(const Duration(milliseconds: 10));
@@ -148,8 +148,8 @@ Future<void> main() async {
 
       for (int i = 0; i < 5; i += 1) {
         final FadeInImageParts parts = findFadeInImage(tester);
-        expect(parts.placeholder.rawImage.image, same(placeholderImage));
-        expect(parts.target.rawImage.image, same(targetImage));
+        expect(parts.placeholder.rawImage.image.isCloneOf(placeholderImage), true);
+        expect(parts.target.rawImage.image.isCloneOf(targetImage), true);
         expect(parts.placeholder.opacity, 0);
         expect(parts.target.opacity, moreOrLessEquals(i / 5));
         await tester.pump(const Duration(milliseconds: 10));
@@ -159,7 +159,7 @@ Future<void> main() async {
         placeholder: placeholderProvider,
         image: imageProvider,
       ));
-      expect(findFadeInImage(tester).target.rawImage.image, same(targetImage));
+      expect(findFadeInImage(tester).target.rawImage.image.isCloneOf(targetImage), true);
       expect(findFadeInImage(tester).target.opacity, 1);
     });
 
@@ -174,7 +174,7 @@ Future<void> main() async {
         image: imageProvider,
       ));
 
-      expect(findFadeInImage(tester).target.rawImage.image, same(targetImage));
+      expect(findFadeInImage(tester).target.rawImage.image.isCloneOf(targetImage), true);
       expect(findFadeInImage(tester).placeholder, isNull);
       expect(findFadeInImage(tester).target.opacity, 1);
     });
@@ -195,7 +195,7 @@ Future<void> main() async {
       final State state = findFadeInImage(tester).state;
       placeholderProvider.complete();
       await tester.pump();
-      expect(findFadeInImage(tester).placeholder.rawImage.image, same(placeholderImage));
+      expect(findFadeInImage(tester).placeholder.rawImage.image.isCloneOf(placeholderImage), true);
 
       await tester.pumpWidget(FadeInImage(
         placeholder: secondPlaceholderProvider,
@@ -207,7 +207,7 @@ Future<void> main() async {
 
       secondPlaceholderProvider.complete();
       await tester.pump();
-      expect(findFadeInImage(tester).placeholder.rawImage.image, same(replacementImage));
+      expect(findFadeInImage(tester).placeholder.rawImage.image.isCloneOf(replacementImage), true);
       expect(findFadeInImage(tester).state, same(state));
     });
 
@@ -263,7 +263,7 @@ Future<void> main() async {
       secondImageProvider.complete();
       await tester.pump();
 
-      expect(findFadeInImage(tester).target.rawImage.image, same(replacementImage));
+      expect(findFadeInImage(tester).target.rawImage.image.isCloneOf(replacementImage), true);
       expect(findFadeInImage(tester).state, same(state));
       expect(findFadeInImage(tester).placeholder.opacity, moreOrLessEquals(1));
       expect(findFadeInImage(tester).target.opacity, moreOrLessEquals(0));

packages/flutter/test/widgets/image_test.dart

@@ -472,7 +472,7 @@ void main() {
     await tester.pump();
     expect(image.toString(), equalsIgnoringHashCodes('_ImageState#00000(stream: ImageStream#00000(OneFrameImageStreamCompleter#00000, $imageString @ 1.0x, 1 listener), pixels: $imageString @ 1.0x, loadingProgress: null, frameNumber: 0, wasSynchronouslyLoaded: false)'));
     await tester.pumpWidget(Container());
-    expect(image.toString(), equalsIgnoringHashCodes('_ImageState#00000(lifecycle state: defunct, not mounted, stream: ImageStream#00000(OneFrameImageStreamCompleter#00000, $imageString @ 1.0x, 0 listeners), pixels: $imageString @ 1.0x, loadingProgress: null, frameNumber: 0, wasSynchronouslyLoaded: false)'));
+    expect(image.toString(), equalsIgnoringHashCodes('_ImageState#00000(lifecycle state: defunct, not mounted, stream: ImageStream#00000(OneFrameImageStreamCompleter#00000, $imageString @ 1.0x, 0 listeners), pixels: null, loadingProgress: null, frameNumber: 0, wasSynchronouslyLoaded: false)'));
   });
 
   testWidgets('Stream completer errors can be listened to by attaching before resolving', (WidgetTester tester) async {
@@ -904,8 +904,8 @@ void main() {
   });
 
   testWidgets('Image State can be reconfigured to use another image', (WidgetTester tester) async {
-    final Image image1 = Image(image: TestImageProvider()..complete(image10x10), width: 10.0, excludeFromSemantics: true);
-    final Image image2 = Image(image: TestImageProvider()..complete(image10x10), width: 20.0, excludeFromSemantics: true);
+    final Image image1 = Image(image: TestImageProvider()..complete(image10x10.clone()), width: 10.0, excludeFromSemantics: true);
+    final Image image2 = Image(image: TestImageProvider()..complete(image10x10.clone()), width: 20.0, excludeFromSemantics: true);
 
     final Column column = Column(children: <Widget>[image1, image2]);
     await tester.pumpWidget(column, null, EnginePhase.layout);
@@ -1039,7 +1039,7 @@ void main() {
   });
 
   testWidgets('Image invokes frameBuilder with correct wasSynchronouslyLoaded=true', (WidgetTester tester) async {
-    final TestImageStreamCompleter streamCompleter = TestImageStreamCompleter(ImageInfo(image: image10x10));
+    final TestImageStreamCompleter streamCompleter = TestImageStreamCompleter(ImageInfo(image: image10x10.clone()));
     final TestImageProvider imageProvider = TestImageProvider(streamCompleter: streamCompleter);
     int lastFrame;
     bool lastFrameWasSync;
@@ -1058,7 +1058,7 @@ void main() {
     expect(lastFrame, 0);
     expect(lastFrameWasSync, isTrue);
     expect(find.byType(RawImage), findsOneWidget);
-    streamCompleter.setData(imageInfo: ImageInfo(image: image10x10));
+    streamCompleter.setData(imageInfo: ImageInfo(image: image10x10.clone()));
     await tester.pump();
     expect(lastFrame, 1);
     expect(lastFrameWasSync, isTrue);
@@ -1474,10 +1474,10 @@ void main() {
     expect(provider1.loadCallCount, 1);
     expect(provider2.loadCallCount, 1);
 
-    provider1.complete(image10x10);
+    provider1.complete(image10x10.clone());
     await tester.idle();
 
-    provider2.complete(image10x10);
+    provider2.complete(image10x10.clone());
     await tester.idle();
 
     expect(imageCache.liveImageCount, 2);
@@ -1763,6 +1763,76 @@ void main() {
     debugOnPaintImage = null;
   });
 
+  testWidgets('Disposes image handle when disposed', (WidgetTester tester) async {
+    final ui.Image image = await tester.runAsync(() => createTestImage(width: 1, height: 1, cache: false));
+
+    expect(image.debugGetOpenHandleStackTraces().length, 1);
+
+    final ImageProvider provider = TestImageProvider(
+      streamCompleter: OneFrameImageStreamCompleter(
+        Future<ImageInfo>.value(
+          ImageInfo(
+            image: image,
+            scale: 1.0,
+            debugLabel: 'TestImage',
+          ),
+        ),
+      ),
+    );
+
+    // creating the provider should not have changed anything, and the provider
+    // now owns the handle.
+    expect(image.debugGetOpenHandleStackTraces().length, 1);
+
+    await tester.pumpWidget(Image(image: provider));
+
+    // Image widget + 1, render object + 1
+    expect(image.debugGetOpenHandleStackTraces().length, 3);
+
+    await tester.pumpWidget(const SizedBox());
+
+    // Image widget and render object go away
+    expect(image.debugGetOpenHandleStackTraces().length, 1);
+
+    await provider.evict();
+
+    tester.binding.scheduleFrame();
+    await tester.pump();
+
+    // Image cache listener go away and Image stream listeners go away.
+    // Image is now at zero.
+    expect(image.debugGetOpenHandleStackTraces().length, 0);
+  }, skip: kIsWeb); // Web does not care about image handle/disposal.
+
+  testWidgets('Keeps stream alive when ticker mode is disabled',  (WidgetTester tester) async {
+    imageCache.maximumSize = 0;
+    final ui.Image image = await tester.runAsync(() => createTestImage(width: 1, height: 1, cache: false));
+    final TestImageProvider provider = TestImageProvider();
+    provider.complete(image);
+
+    await tester.pumpWidget(
+      TickerMode(
+        enabled: true,
+        child: Image(image: provider),
+      ),
+    );
+    expect(find.byType(Image), findsOneWidget);
+
+    await tester.pumpWidget(TickerMode(
+        enabled: false,
+        child: Image(image: provider),
+      ),
+    );
+    expect(find.byType(Image), findsOneWidget);
+
+    await tester.pumpWidget(TickerMode(
+        enabled: true,
+        child: Image(image: provider),
+      ),
+    );
+    expect(find.byType(Image), findsOneWidget);
+  });
+
   testWidgets('Load a good image after a bad image was loaded should not call errorBuilder', (WidgetTester tester) async {
     final UniqueKey errorKey = UniqueKey();
     final ui.Image image = await tester.runAsync(() => createTestImage());
@@ -1899,6 +1969,12 @@ class TestImageProvider extends ImageProvider<Object> {
   String toString() => '${describeIdentity(this)}()';
 }
 
+class SimpleTestImageStreamCompleter extends ImageStreamCompleter {
+  void testSetImage(ui.Image image) {
+    setImage(ImageInfo(image: image, scale: 1.0));
+  }
+}
+
 class TestImageStreamCompleter extends ImageStreamCompleter {
   TestImageStreamCompleter([this._currentImage]);
 
@@ -1909,7 +1985,7 @@ class TestImageStreamCompleter extends ImageStreamCompleter {
   void addListener(ImageStreamListener listener) {
     listeners.add(listener);
     if (_currentImage != null) {
-      listener.onImage(_currentImage, true);
+      listener.onImage(_currentImage.clone(), true);
     }
   }
 
@@ -1923,12 +1999,13 @@ class TestImageStreamCompleter extends ImageStreamCompleter {
     ImageChunkEvent chunkEvent,
   }) {
     if (imageInfo != null) {
+      _currentImage?.dispose();
       _currentImage = imageInfo;
     }
     final List<ImageStreamListener> localListeners = listeners.toList();
     for (final ImageStreamListener listener in localListeners) {
       if (imageInfo != null) {
-        listener.onImage(imageInfo, false);
+        listener.onImage(imageInfo.clone(), false);
       }
       if (chunkEvent != null && listener.onChunk != null) {
         listener.onChunk(chunkEvent);

packages/flutter_test/lib/src/animation_sheet.dart

@@ -166,7 +166,7 @@ class AnimationSheetBuilder {
       key: key,
       cellSize: frameSize,
       children: frames.map((ui.Image image) => RawImage(
-        image: image,
+        image: image.clone(),
         width: frameSize.width,
         height: frameSize.height,
       )).toList(),

packages/flutter_test/lib/src/image.dart

@@ -38,12 +38,12 @@ Future<ui.Image> createTestImage({
 
   final int cacheKey = hashValues(width, height);
   if (cache && _cache.containsKey(cacheKey)) {
-    return _cache[cacheKey]!;
+    return _cache[cacheKey]!.clone();
   }
 
   final ui.Image image = await _createImage(width, height);
   if (cache) {
-    _cache[cacheKey] = image;
+    _cache[cacheKey] = image.clone();
   }
   return image;
 });