Revert "Share engine layers with the framework" (flutter#6412)

Reverts flutter#6406

We need to fix the SkiaGPUObject issue of the raster cache SkImage before merging this PR.

ci/licenses_golden/licenses_flutter

@@ -475,8 +475,6 @@ TYPE: LicenseType.bsd
 FILE: ../../../flutter/flutter_kernel_transformers/lib/track_widget_constructor_locations.dart
 FILE: ../../../flutter/fml/paths_unittests.cc
 FILE: ../../../flutter/lib/ui/isolate_name_server.dart
-FILE: ../../../flutter/lib/ui/painting/engine_layer.cc
-FILE: ../../../flutter/lib/ui/painting/engine_layer.h
 FILE: ../../../flutter/lib/ui/painting/image_encoding.cc
 FILE: ../../../flutter/lib/ui/painting/image_encoding.h
 FILE: ../../../flutter/lib/ui/plugins.dart

flow/layers/container_layer.cc

@@ -10,7 +10,7 @@ ContainerLayer::ContainerLayer() {}
 
 ContainerLayer::~ContainerLayer() = default;
 
-void ContainerLayer::Add(std::shared_ptr<Layer> layer) {
+void ContainerLayer::Add(std::unique_ptr<Layer> layer) {
   layer->set_parent(this);
   layers_.push_back(std::move(layer));
 }

flow/layers/container_layer.h

@@ -15,15 +15,15 @@ class ContainerLayer : public Layer {
   ContainerLayer();
   ~ContainerLayer() override;
 
-  void Add(std::shared_ptr<Layer> layer);
+  void Add(std::unique_ptr<Layer> layer);
 
   void Preroll(PrerollContext* context, const SkMatrix& matrix) override;
 
 #if defined(OS_FUCHSIA)
   void UpdateScene(SceneUpdateContext& context) override;
 #endif  // defined(OS_FUCHSIA)
 
-  const std::vector<std::shared_ptr<Layer>>& layers() const { return layers_; }
+  const std::vector<std::unique_ptr<Layer>>& layers() const { return layers_; }
 
  protected:
   void PrerollChildren(PrerollContext* context,
@@ -36,7 +36,7 @@ class ContainerLayer : public Layer {
 #endif  // defined(OS_FUCHSIA)
 
  private:
-  std::vector<std::shared_ptr<Layer>> layers_;
+  std::vector<std::unique_ptr<Layer>> layers_;
 
   FML_DISALLOW_COPY_AND_ASSIGN(ContainerLayer);
 };

flow/layers/layer_tree.h

@@ -38,7 +38,7 @@ class LayerTree {
 
   Layer* root_layer() const { return root_layer_.get(); }
 
-  void set_root_layer(std::shared_ptr<Layer> root_layer) {
+  void set_root_layer(std::unique_ptr<Layer> root_layer) {
     root_layer_ = std::move(root_layer);
   }
 
@@ -73,7 +73,7 @@ class LayerTree {
 
  private:
   SkISize frame_size_;  // Physical pixels.
-  std::shared_ptr<Layer> root_layer_;
+  std::unique_ptr<Layer> root_layer_;
   fml::TimeDelta construction_time_;
   uint32_t rasterizer_tracing_threshold_;
   bool checkerboard_raster_cache_images_;

lib/ui/BUILD.gn

@@ -23,8 +23,6 @@ source_set("ui") {
     "painting/canvas.h",
     "painting/codec.cc",
     "painting/codec.h",
-    "painting/engine_layer.h",
-    "painting/engine_layer.cc",
     "painting/frame_info.cc",
     "painting/frame_info.h",
     "painting/gradient.cc",

lib/ui/compositing.dart

@@ -69,7 +69,7 @@ class SceneBuilder extends NativeFieldWrapperClass2 {
   /// This is equivalent to [pushTransform] with a matrix with only translation.
   ///
   /// See [pop] for details about the operation stack.
-  EngineLayer pushOffset(double dx, double dy) native 'SceneBuilder_pushOffset';
+  void pushOffset(double dx, double dy) native 'SceneBuilder_pushOffset';
 
   /// Pushes a rectangular clip operation onto the operation stack.
   ///
@@ -177,10 +177,10 @@ class SceneBuilder extends NativeFieldWrapperClass2 {
   ///
   /// See [pop] for details about the operation stack, and [Clip] for different clip modes.
   // ignore: deprecated_member_use
-  EngineLayer pushPhysicalShape({ Path path, double elevation, Color color, Color shadowColor, Clip clipBehavior = defaultClipBehavior}) {
-    return _pushPhysicalShape(path, elevation, color.value, shadowColor?.value ?? 0xFF000000, clipBehavior.index);
+  void pushPhysicalShape({ Path path, double elevation, Color color, Color shadowColor, Clip clipBehavior = defaultClipBehavior}) {
+    _pushPhysicalShape(path, elevation, color.value, shadowColor?.value ?? 0xFF000000, clipBehavior.index);
   }
-  EngineLayer _pushPhysicalShape(Path path, double elevation, int color, int shadowColor, int clipBehavior) native
+  void _pushPhysicalShape(Path path, double elevation, int color, int shadowColor, int clipBehavior) native
     'SceneBuilder_pushPhysicalShape';
 
   /// Ends the effect of the most recently pushed operation.
@@ -191,14 +191,6 @@ class SceneBuilder extends NativeFieldWrapperClass2 {
   /// stack.
   void pop() native 'SceneBuilder_pop';
 
-  /// Add a retained engine layer subtree from previous frames.
-  ///
-  /// All the engine layers that are in the subtree of the retained layer will
-  /// be automatically appended to the current engine layer tree. Therefore,
-  /// once this is called, there's no need to call [addToScene] for its children
-  /// layers.
-  EngineLayer addRetained(EngineLayer retainedLayer) native 'SceneBuilder_addRetained';
-
   /// Adds an object to the scene that displays performance statistics.
   ///
   /// Useful during development to assess the performance of the application.

lib/ui/compositing/scene.cc

@@ -26,7 +26,7 @@ IMPLEMENT_WRAPPERTYPEINFO(ui, Scene);
 
 DART_BIND_ALL(Scene, FOR_EACH_BINDING)
 
-fml::RefPtr<Scene> Scene::create(std::shared_ptr<flow::Layer> rootLayer,
+fml::RefPtr<Scene> Scene::create(std::unique_ptr<flow::Layer> rootLayer,
                                  uint32_t rasterizerTracingThreshold,
                                  bool checkerboardRasterCacheImages,
                                  bool checkerboardOffscreenLayers) {
@@ -35,7 +35,7 @@ fml::RefPtr<Scene> Scene::create(std::shared_ptr<flow::Layer> rootLayer,
       checkerboardRasterCacheImages, checkerboardOffscreenLayers);
 }
 
-Scene::Scene(std::shared_ptr<flow::Layer> rootLayer,
+Scene::Scene(std::unique_ptr<flow::Layer> rootLayer,
              uint32_t rasterizerTracingThreshold,
              bool checkerboardRasterCacheImages,
              bool checkerboardOffscreenLayers)

lib/ui/compositing/scene.h

@@ -24,7 +24,7 @@ class Scene : public RefCountedDartWrappable<Scene> {
 
  public:
   ~Scene() override;
-  static fml::RefPtr<Scene> create(std::shared_ptr<flow::Layer> rootLayer,
+  static fml::RefPtr<Scene> create(std::unique_ptr<flow::Layer> rootLayer,
                                    uint32_t rasterizerTracingThreshold,
                                    bool checkerboardRasterCacheImages,
                                    bool checkerboardOffscreenLayers);
@@ -40,7 +40,7 @@ class Scene : public RefCountedDartWrappable<Scene> {
   static void RegisterNatives(tonic::DartLibraryNatives* natives);
 
  private:
-  explicit Scene(std::shared_ptr<flow::Layer> rootLayer,
+  explicit Scene(std::unique_ptr<flow::Layer> rootLayer,
                  uint32_t rasterizerTracingThreshold,
                  bool checkerboardRasterCacheImages,
                  bool checkerboardOffscreenLayers);

lib/ui/compositing/scene_builder.cc

@@ -53,7 +53,6 @@ IMPLEMENT_WRAPPERTYPEINFO(ui, SceneBuilder);
   V(SceneBuilder, pushShaderMask)                   \
   V(SceneBuilder, pushPhysicalShape)                \
   V(SceneBuilder, pop)                              \
-  V(SceneBuilder, addRetained)                      \
   V(SceneBuilder, addPicture)                       \
   V(SceneBuilder, addTexture)                       \
   V(SceneBuilder, addChildScene)                    \
@@ -81,12 +80,11 @@ void SceneBuilder::pushTransform(const tonic::Float64List& matrix4) {
   PushLayer(std::move(layer));
 }
 
-fml::RefPtr<EngineLayer> SceneBuilder::pushOffset(double dx, double dy) {
+void SceneBuilder::pushOffset(double dx, double dy) {
   SkMatrix sk_matrix = SkMatrix::MakeTrans(dx, dy);
-  auto layer = std::make_shared<flow::TransformLayer>();
+  auto layer = std::make_unique<flow::TransformLayer>();
   layer->set_transform(sk_matrix);
-  PushLayer(layer);
-  return EngineLayer::MakeRetained(layer);
+  PushLayer(std::move(layer));
 }
 
 void SceneBuilder::pushClipRect(double left,
@@ -150,29 +148,21 @@ void SceneBuilder::pushShaderMask(Shader* shader,
   PushLayer(std::move(layer));
 }
 
-fml::RefPtr<EngineLayer> SceneBuilder::pushPhysicalShape(const CanvasPath* path,
-                                                         double elevation,
-                                                         int color,
-                                                         int shadow_color,
-                                                         int clipBehavior) {
+void SceneBuilder::pushPhysicalShape(const CanvasPath* path,
+                                     double elevation,
+                                     int color,
+                                     int shadow_color,
+                                     int clipBehavior) {
   const SkPath& sk_path = path->path();
   flow::Clip clip_behavior = static_cast<flow::Clip>(clipBehavior);
-  auto layer = std::make_shared<flow::PhysicalShapeLayer>(clip_behavior);
+  auto layer = std::make_unique<flow::PhysicalShapeLayer>(clip_behavior);
   layer->set_path(sk_path);
   layer->set_elevation(elevation);
   layer->set_color(static_cast<SkColor>(color));
   layer->set_shadow_color(static_cast<SkColor>(shadow_color));
   layer->set_device_pixel_ratio(
       UIDartState::Current()->window()->viewport_metrics().device_pixel_ratio);
-  PushLayer(layer);
-  return EngineLayer::MakeRetained(layer);
-}
-
-void SceneBuilder::addRetained(fml::RefPtr<EngineLayer> retainedLayer) {
-  if (!current_layer_) {
-    return;
-  }
-  current_layer_->Add(retainedLayer->Layer());
+  PushLayer(std::move(layer));
 }
 
 void SceneBuilder::pop() {
@@ -270,7 +260,7 @@ fml::RefPtr<Scene> SceneBuilder::build() {
   return scene;
 }
 
-void SceneBuilder::PushLayer(std::shared_ptr<flow::ContainerLayer> layer) {
+void SceneBuilder::PushLayer(std::unique_ptr<flow::ContainerLayer> layer) {
   FML_DCHECK(layer);
 
   if (!root_layer_) {

lib/ui/compositing/scene_builder.h

@@ -12,7 +12,6 @@
 #include "flutter/lib/ui/compositing/scene.h"
 #include "flutter/lib/ui/compositing/scene_host.h"
 #include "flutter/lib/ui/dart_wrapper.h"
-#include "flutter/lib/ui/painting/engine_layer.h"
 #include "flutter/lib/ui/painting/image_filter.h"
 #include "flutter/lib/ui/painting/path.h"
 #include "flutter/lib/ui/painting/picture.h"
@@ -34,7 +33,7 @@ class SceneBuilder : public RefCountedDartWrappable<SceneBuilder> {
   ~SceneBuilder() override;
 
   void pushTransform(const tonic::Float64List& matrix4);
-  fml::RefPtr<EngineLayer> pushOffset(double dx, double dy);
+  void pushOffset(double dx, double dy);
   void pushClipRect(double left,
                     double right,
                     double top,
@@ -51,13 +50,11 @@ class SceneBuilder : public RefCountedDartWrappable<SceneBuilder> {
                       double maskRectTop,
                       double maskRectBottom,
                       int blendMode);
-  fml::RefPtr<EngineLayer> pushPhysicalShape(const CanvasPath* path,
-                                             double elevation,
-                                             int color,
-                                             int shadowColor,
-                                             int clipBehavior);
-
-  void addRetained(fml::RefPtr<EngineLayer> retainedLayer);
+  void pushPhysicalShape(const CanvasPath* path,
+                         double elevation,
+                         int color,
+                         int shadowColor,
+                         int clipBehavior);
 
   void pop();
 
@@ -95,14 +92,14 @@ class SceneBuilder : public RefCountedDartWrappable<SceneBuilder> {
  private:
   SceneBuilder();
 
-  std::shared_ptr<flow::ContainerLayer> root_layer_;
+  std::unique_ptr<flow::ContainerLayer> root_layer_;
   flow::ContainerLayer* current_layer_ = nullptr;
 
   int rasterizer_tracing_threshold_ = 0;
   bool checkerboard_raster_cache_images_ = false;
   bool checkerboard_offscreen_layers_ = false;
 
-  void PushLayer(std::shared_ptr<flow::ContainerLayer> layer);
+  void PushLayer(std::unique_ptr<flow::ContainerLayer> layer);
 
   FML_DISALLOW_COPY_AND_ASSIGN(SceneBuilder);
 };

lib/ui/dart_ui.cc

@@ -11,7 +11,6 @@
 #include "flutter/lib/ui/isolate_name_server/isolate_name_server_natives.h"
 #include "flutter/lib/ui/painting/canvas.h"
 #include "flutter/lib/ui/painting/codec.h"
-#include "flutter/lib/ui/painting/engine_layer.h"
 #include "flutter/lib/ui/painting/frame_info.h"
 #include "flutter/lib/ui/painting/gradient.h"
 #include "flutter/lib/ui/painting/image.h"
@@ -59,7 +58,6 @@ void DartUI::InitForGlobal() {
     CanvasPathMeasure::RegisterNatives(g_natives);
     Codec::RegisterNatives(g_natives);
     DartRuntimeHooks::RegisterNatives(g_natives);
-    EngineLayer::RegisterNatives(g_natives);
     FrameInfo::RegisterNatives(g_natives);
     ImageFilter::RegisterNatives(g_natives);
     ImageShader::RegisterNatives(g_natives);

lib/ui/painting.dart

@@ -1742,13 +1742,6 @@ enum PathOperation {
   reverseDifference,
 }
 
-/// A handle for the framework to hold and retain an engine layer across frames.
-class EngineLayer extends NativeFieldWrapperClass2 {
-  /// This class is created by the engine, and should not be instantiated
-  /// or extended directly.
-  EngineLayer._();
-}
-
 /// A complex, one-dimensional subset of a plane.
 ///
 /// A path consists of a number of subpaths, and a _current point_.