test that is hopefully not flaky!

ci/licenses_golden/licenses_flutter

@@ -338,6 +338,7 @@ FILE: ../../../flutter/lib/ui/painting/image_decoder.h
 FILE: ../../../flutter/lib/ui/painting/image_decoder_unittests.cc
 FILE: ../../../flutter/lib/ui/painting/image_descriptor.cc
 FILE: ../../../flutter/lib/ui/painting/image_descriptor.h
+FILE: ../../../flutter/lib/ui/painting/image_dispose_unittests.cc
 FILE: ../../../flutter/lib/ui/painting/image_encoding.cc
 FILE: ../../../flutter/lib/ui/painting/image_encoding.h
 FILE: ../../../flutter/lib/ui/painting/image_encoding_unittests.cc

lib/ui/BUILD.gn

@@ -181,6 +181,7 @@ if (enable_unittests) {
     public_configs = [ "//flutter:export_dynamic_symbols" ]
 
     sources = [
+      "painting/image_dispose_unittests.cc",
       "painting/image_encoding_unittests.cc",
       "painting/vertices_unittests.cc",
       "window/platform_configuration_unittests.cc",

lib/ui/fixtures/ui_test.dart

@@ -3,6 +3,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:async';
 import 'dart:typed_data';
 import 'dart:ui';
 
@@ -73,3 +74,61 @@ Future<void> encodeImageProducesExternalUint8List() async {
 void _encodeImage(Image i, int format, void Function(Uint8List result))
   native 'EncodeImage';
 void _validateExternal(Uint8List result) native 'ValidateExternal';
+
+@pragma('vm:entry-point')
+Future<void> pumpImage() async {
+  const int width = 8000;
+  const int height = 8000;
+  final Completer<Image> completer = Completer<Image>();
+  decodeImageFromPixels(
+    Uint8List.fromList(List<int>.filled(width * height * 4, 0xFF)),
+    width,
+    height,
+    PixelFormat.rgba8888,
+    (Image image) => completer.complete(image),
+  );
+  final Image image = await completer.future;
+
+  final FrameCallback renderBlank = (Duration duration) {
+    image.dispose();
+
+    final PictureRecorder recorder = PictureRecorder();
+    final Canvas canvas = Canvas(recorder);
+    canvas.drawRect(Rect.largest, Paint());
+    final Picture picture = recorder.endRecording();
+
+    final SceneBuilder builder = SceneBuilder();
+    builder.addPicture(Offset.zero, picture);
+
+    final Scene scene = builder.build();
+    window.render(scene);
+    scene.dispose();
+    window.onBeginFrame = (Duration duration) {
+      window.onDrawFrame = _onBeginFrameDone;
+    };
+    window.scheduleFrame();
+  };
+
+  final FrameCallback renderImage = (Duration duration) {
+    final PictureRecorder recorder = PictureRecorder();
+    final Canvas canvas = Canvas(recorder);
+    canvas.drawImage(image, Offset.zero, Paint());
+    final Picture picture = recorder.endRecording();
+
+    final SceneBuilder builder = SceneBuilder();
+    builder.addPicture(Offset.zero, picture);
+
+    _captureImageAndPicture(image, picture);
+
+    final Scene scene = builder.build();
+    window.render(scene);
+    scene.dispose();
+    window.onBeginFrame = renderBlank;
+    window.scheduleFrame();
+  };
+
+  window.onBeginFrame = renderImage;
+  window.scheduleFrame();
+}
+void _captureImageAndPicture(Image image, Picture picture) native 'CaptureImageAndPicture';
+Future<void> _onBeginFrameDone() native 'OnBeginFrameDone';

lib/ui/painting/image_dispose_unittests.cc

@@ -0,0 +1,97 @@
+
+// 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.
+
+#define FML_USED_ON_EMBEDDER
+
+#include "flutter/common/task_runners.h"
+#include "flutter/fml/synchronization/waitable_event.h"
+#include "flutter/lib/ui/painting/image.h"
+#include "flutter/lib/ui/painting/picture.h"
+#include "flutter/runtime/dart_vm.h"
+#include "flutter/shell/common/shell_test.h"
+#include "flutter/shell/common/thread_host.h"
+#include "flutter/testing/testing.h"
+
+namespace flutter {
+namespace testing {
+
+class ImageDisposeTest : public ShellTest {
+ public:
+  template <class T>
+  T* GetNativePeer(Dart_NativeArguments args, int index) {
+    auto handle = Dart_GetNativeArgument(args, index);
+    intptr_t peer = 0;
+    EXPECT_FALSE(Dart_IsError(Dart_GetNativeInstanceField(
+        handle, tonic::DartWrappable::kPeerIndex, &peer)));
+    return reinterpret_cast<T*>(peer);
+  }
+
+  // Used to wait on Dart callbacks or Shell task runner flushing
+  fml::AutoResetWaitableEvent message_latch_;
+
+  sk_sp<SkPicture> current_picture_;
+  sk_sp<SkImage> current_image_;
+};
+
+TEST_F(ImageDisposeTest, ImageReleasedAfterFrame) {
+  auto native_capture_image_and_picture = [&](Dart_NativeArguments args) {
+    CanvasImage* image = GetNativePeer<CanvasImage>(args, 0);
+    Picture* picture = GetNativePeer<Picture>(args, 1);
+    ASSERT_FALSE(image->image()->unique());
+    ASSERT_FALSE(picture->picture()->unique());
+    current_image_ = image->image();
+    current_picture_ = picture->picture();
+  };
+
+  auto native_on_begin_frame_done = [&](Dart_NativeArguments args) {
+    message_latch_.Signal();
+  };
+
+  Settings settings = CreateSettingsForFixture();
+  auto task_runner = CreateNewThread();
+  TaskRunners task_runners("test",                  // label
+                           GetCurrentTaskRunner(),  // platform
+                           task_runner,             // raster
+                           task_runner,             // ui
+                           task_runner              // io
+  );
+
+  AddNativeCallback("CaptureImageAndPicture",
+                    CREATE_NATIVE_ENTRY(native_capture_image_and_picture));
+  AddNativeCallback("OnBeginFrameDone",
+                    CREATE_NATIVE_ENTRY(native_on_begin_frame_done));
+
+  std::unique_ptr<Shell> shell = CreateShell(std::move(settings), task_runners);
+
+  ASSERT_TRUE(shell->IsSetup());
+
+  SetViewportMetrics(shell.get(), 800, 600);
+
+  shell->GetPlatformView()->NotifyCreated();
+
+  auto configuration = RunConfiguration::InferFromSettings(settings);
+  configuration.SetEntrypoint("pumpImage");
+
+  shell->RunEngine(std::move(configuration), [&](auto result) {
+    ASSERT_EQ(result, Engine::RunStatus::Success);
+  });
+
+  message_latch_.Wait();
+
+  ASSERT_TRUE(current_picture_);
+  ASSERT_TRUE(current_image_);
+
+  EXPECT_TRUE(current_picture_->unique());
+  current_picture_.reset();
+
+  EXPECT_TRUE(current_image_->unique());
+  current_image_.reset();
+
+  shell->GetPlatformView()->NotifyDestroyed();
+  DestroyShell(std::move(shell), std::move(task_runners));
+}
+
+}  // namespace testing
+}  // namespace flutter

shell/common/shell_test.cc

@@ -106,6 +106,40 @@ void ShellTest::VSyncFlush(Shell* shell, bool& will_draw_new_frame) {
   latch.Wait();
 }
 
+void ShellTest::SetViewportMetrics(Shell* shell, double width, double height) {
+  flutter::ViewportMetrics viewport_metrics = {
+      1,       // device pixel ratio
+      width,   // physical width
+      height,  // physical height
+      0,       // padding top
+      0,       // padding right
+      0,       // padding bottom
+      0,       // padding left
+      0,       // view inset top
+      0,       // view inset right
+      0,       // view inset bottom
+      0,       // view inset left
+      0,       // gesture inset top
+      0,       // gesture inset right
+      0,       // gesture inset bottom
+      0        // gesture inset left
+  };
+  // Set viewport to nonempty, and call Animator::BeginFrame to make the layer
+  // tree pipeline nonempty. Without either of this, the layer tree below
+  // won't be rasterized.
+  fml::AutoResetWaitableEvent latch;
+  shell->GetTaskRunners().GetUITaskRunner()->PostTask(
+      [&latch, engine = shell->weak_engine_, viewport_metrics]() {
+        engine->SetViewportMetrics(std::move(viewport_metrics));
+        const auto frame_begin_time = fml::TimePoint::Now();
+        const auto frame_end_time =
+            frame_begin_time + fml::TimeDelta::FromSecondsF(1.0 / 60.0);
+        engine->animator_->BeginFrame(frame_begin_time, frame_end_time);
+        latch.Signal();
+      });
+  latch.Wait();
+}
+
 void ShellTest::PumpOneFrame(Shell* shell,
                              double width,
                              double height,

shell/common/shell_test.h

@@ -63,6 +63,8 @@ class ShellTest : public FixtureTest {
   /// in PumpOneFrame.
   using LayerTreeBuilder =
       std::function<void(std::shared_ptr<ContainerLayer> root)>;
+
+  static void SetViewportMetrics(Shell* shell, double width, double height);
   static void PumpOneFrame(Shell* shell,
                            double width = 1,
                            double height = 1,