fuchsia: Remove dead code / break dependencies

The fuchsia code around metrics and sizing was just sending this
information through a side-channel, when the engine already had the
information available.  So, delete all of it to make future CLs simpler.

Additionally, the SceneUpdateContext has many unneccesary dependencies
re: metrics and PaintTasks.  Break those to make future CLs simpler.

Tested: Ran all unittests and ran workstation on Fuchsia
BUG: 53062, 53063

Author: arbreng

flow/compositor_context.cc

@@ -87,7 +87,7 @@ RasterStatus CompositorContext::ScopedFrame::Raster(
   if (canvas()) {
     if (needs_save_layer) {
       FML_LOG(INFO) << "Using SaveLayer to protect non-readback surface";
-      SkRect bounds = SkRect::Make(layer_tree.frame_size());
+      SkRect bounds = SkRect::MakeSize(layer_tree.frame_size());
       SkPaint paint;
       paint.setBlendMode(SkBlendMode::kSrc);
       canvas()->saveLayer(&bounds, &paint);

flow/layers/backdrop_filter_layer.cc

@@ -9,6 +9,8 @@ namespace flutter {
 BackdropFilterLayer::BackdropFilterLayer(sk_sp<SkImageFilter> filter)
     : filter_(std::move(filter)) {}
 
+BackdropFilterLayer::~BackdropFilterLayer() = default;
+
 void BackdropFilterLayer::Preroll(PrerollContext* context,
                                   const SkMatrix& matrix) {
   Layer::AutoPrerollSaveLayerState save =
@@ -23,7 +25,7 @@ void BackdropFilterLayer::Paint(PaintContext& context) const {
   Layer::AutoSaveLayer save = Layer::AutoSaveLayer::Create(
       context,
       SkCanvas::SaveLayerRec{&paint_bounds(), nullptr, filter_.get(), 0});
-  PaintChildren(context);
+  ContainerLayer::Paint(context);
 }
 
 }  // namespace flutter

flow/layers/backdrop_filter_layer.h

@@ -6,17 +6,16 @@
 #define FLUTTER_FLOW_LAYERS_BACKDROP_FILTER_LAYER_H_
 
 #include "flutter/flow/layers/container_layer.h"
-
 #include "third_party/skia/include/core/SkImageFilter.h"
 
 namespace flutter {
 
 class BackdropFilterLayer : public ContainerLayer {
  public:
   BackdropFilterLayer(sk_sp<SkImageFilter> filter);
+  ~BackdropFilterLayer() override;
 
   void Preroll(PrerollContext* context, const SkMatrix& matrix) override;
-
   void Paint(PaintContext& context) const override;
 
  private:

flow/layers/backdrop_filter_layer_unittests.cc

@@ -23,7 +23,6 @@ TEST_F(BackdropFilterLayerTest, PaintingEmptyLayerDies) {
   layer->Preroll(preroll_context(), SkMatrix());
   EXPECT_EQ(layer->paint_bounds(), kEmptyRect);
   EXPECT_FALSE(layer->needs_painting());
-  EXPECT_FALSE(layer->needs_system_composite());
 
   EXPECT_DEATH_IF_SUPPORTED(layer->Paint(paint_context()),
                             "needs_painting\\(\\)");
@@ -206,7 +205,7 @@ TEST_F(BackdropFilterLayerTest, Readback) {
 
   // BDF with no filter blocks child with readback
   auto mock_layer =
-      std::make_shared<MockLayer>(SkPath(), SkPaint(), false, false, true);
+      std::make_shared<MockLayer>(SkPath(), SkPaint(), false, true);
   layer2->Add(mock_layer);
   preroll_context()->surface_needs_readback = false;
   layer2->Preroll(preroll_context(), initial_transform);

flow/layers/child_scene_layer.cc

@@ -4,31 +4,36 @@
 
 #include "flutter/flow/layers/child_scene_layer.h"
 
-#include "flutter/flow/view_holder.h"
-
 namespace flutter {
 
-ChildSceneLayer::ChildSceneLayer(zx_koid_t layer_id,
-                                 const SkPoint& offset,
+ChildSceneLayer::ChildSceneLayer(const SkPoint& offset,
                                  const SkSize& size,
+                                 zx_koid_t layer_id,
                                  bool hit_testable)
-    : layer_id_(layer_id),
-      offset_(offset),
+    : offset_(offset),
       size_(size),
+      layer_id_(layer_id),
       hit_testable_(hit_testable) {}
 
+ChildSceneLayer::~ChildSceneLayer() = default;
+
 void ChildSceneLayer::Preroll(PrerollContext* context, const SkMatrix& matrix) {
   TRACE_EVENT0("flutter", "ChildSceneLayer::Preroll");
-  set_needs_system_composite(true);
 
+  context->has_platform_view = true;
+  context->platform_view_exists_below = true;
   CheckForChildLayerBelow(context);
 
-  context->child_scene_layer_exists_below = true;
-
   // An alpha "hole punch" is required if the frame behind us is not opaque.
-  if (!context->is_opaque) {
-    set_paint_bounds(
-        SkRect::MakeXYWH(offset_.fX, offset_.fY, size_.fWidth, size_.fHeight));
+  for (auto i = context->mutators_stack.Bottom();
+       i != context->mutators_stack.Top(); ++i) {
+    const auto& mutator = *i;
+    if (mutator->GetType() == MutatorType::opacity &&
+        mutator->GetAlpha() < 255) {
+      set_paint_bounds(SkRect::MakeXYWH(offset_.fX, offset_.fY, size_.fWidth,
+                                        size_.fHeight));
+      break;
+    }
   }
 }
 
@@ -50,14 +55,7 @@ void ChildSceneLayer::UpdateScene(SceneUpdateContext& context) {
   TRACE_EVENT0("flutter", "ChildSceneLayer::UpdateScene");
   FML_DCHECK(needs_system_composite());
 
-  Layer::UpdateScene(context);
-
-  auto* view_holder = ViewHolder::FromId(layer_id_);
-  FML_DCHECK(view_holder);
-
-  view_holder->UpdateScene(context, offset_, size_,
-                           SkScalarRoundToInt(context.alphaf() * 255),
-                           hit_testable_);
+  context.UpdateScene(layer_id_, offset_, size_, hit_testable_);
 }
 
 }  // namespace flutter

flow/layers/child_scene_layer.h

@@ -5,34 +5,29 @@
 #ifndef FLUTTER_FLOW_LAYERS_CHILD_SCENE_LAYER_H_
 #define FLUTTER_FLOW_LAYERS_CHILD_SCENE_LAYER_H_
 
+#include "flutter/flow/layers/layer.h"
 #include "third_party/skia/include/core/SkMatrix.h"
 #include "third_party/skia/include/core/SkPoint.h"
 #include "third_party/skia/include/core/SkSize.h"
 
-#include "flutter/flow/layers/layer.h"
-#include "flutter/flow/scene_update_context.h"
-
 namespace flutter {
 
-// Layer that represents an embedded child.
 class ChildSceneLayer : public Layer {
  public:
-  ChildSceneLayer(zx_koid_t layer_id,
-                  const SkPoint& offset,
+  ChildSceneLayer(const SkPoint& offset,
                   const SkSize& size,
+                  zx_koid_t layer_id,
                   bool hit_testable);
-  ~ChildSceneLayer() override = default;
+  ~ChildSceneLayer() override;
 
   void Preroll(PrerollContext* context, const SkMatrix& matrix) override;
-
   void Paint(PaintContext& context) const override;
-
   void UpdateScene(SceneUpdateContext& context) override;
 
  private:
-  zx_koid_t layer_id_ = ZX_KOID_INVALID;
   SkPoint offset_;
   SkSize size_;
+  zx_koid_t layer_id_ = ZX_KOID_INVALID;
   bool hit_testable_ = true;
 
   FML_DISALLOW_COPY_AND_ASSIGN(ChildSceneLayer);

flow/layers/clip_path_layer.cc

@@ -4,19 +4,15 @@
 
 #include "flutter/flow/layers/clip_path_layer.h"
 
-#if defined(LEGACY_FUCHSIA_EMBEDDER)
-
-#include "lib/ui/scenic/cpp/commands.h"
-
-#endif
-
 namespace flutter {
 
 ClipPathLayer::ClipPathLayer(const SkPath& clip_path, Clip clip_behavior)
     : clip_path_(clip_path), clip_behavior_(clip_behavior) {
   FML_DCHECK(clip_behavior != Clip::none);
 }
 
+ClipPathLayer::~ClipPathLayer() = default;
+
 void ClipPathLayer::Preroll(PrerollContext* context, const SkMatrix& matrix) {
   TRACE_EVENT0("flutter", "ClipPathLayer::Preroll");
 
@@ -29,30 +25,16 @@ void ClipPathLayer::Preroll(PrerollContext* context, const SkMatrix& matrix) {
     Layer::AutoPrerollSaveLayerState save =
         Layer::AutoPrerollSaveLayerState::Create(context, UsesSaveLayer());
     context->mutators_stack.PushClipPath(clip_path_);
-    SkRect child_paint_bounds = SkRect::MakeEmpty();
-    PrerollChildren(context, matrix, &child_paint_bounds);
+    ContainerLayer::Preroll(context, matrix);
 
-    if (child_paint_bounds.intersect(clip_path_bounds)) {
-      set_paint_bounds(child_paint_bounds);
+    if (clip_path_bounds.intersect(paint_bounds())) {
+      set_paint_bounds(clip_path_bounds);
     }
     context->mutators_stack.Pop();
   }
   context->cull_rect = previous_cull_rect;
 }
 
-#if defined(LEGACY_FUCHSIA_EMBEDDER)
-
-void ClipPathLayer::UpdateScene(SceneUpdateContext& context) {
-  TRACE_EVENT0("flutter", "ClipPathLayer::UpdateScene");
-  FML_DCHECK(needs_system_composite());
-
-  // TODO(liyuqian): respect clip_behavior_
-  SceneUpdateContext::Clip clip(context, clip_path_.getBounds());
-  UpdateSceneChildren(context);
-}
-
-#endif
-
 void ClipPathLayer::Paint(PaintContext& context) const {
   TRACE_EVENT0("flutter", "ClipPathLayer::Paint");
   FML_DCHECK(needs_painting());
@@ -69,10 +51,23 @@ void ClipPathLayer::Paint(PaintContext& context) const {
   if (UsesSaveLayer()) {
     context.internal_nodes_canvas->saveLayer(paint_bounds(), nullptr);
   }
-  PaintChildren(context);
+  ContainerLayer::Paint(context);
   if (UsesSaveLayer()) {
     context.internal_nodes_canvas->restore();
   }
 }
 
+#if defined(LEGACY_FUCHSIA_EMBEDDER)
+
+void ClipPathLayer::UpdateScene(SceneUpdateContext& context) {
+  TRACE_EVENT0("flutter", "ClipPathLayer::UpdateScene");
+  FML_DCHECK(needs_system_composite());
+
+  // TODO(liyuqian): respect clip_behavior_
+  SceneUpdateContext::Clip clip(context, clip_path_.getBounds());
+  ContainerLayer::UpdateScene(context);
+}
+
+#endif
+
 }  // namespace flutter

flow/layers/clip_path_layer.h

@@ -6,15 +6,16 @@
 #define FLUTTER_FLOW_LAYERS_CLIP_PATH_LAYER_H_
 
 #include "flutter/flow/layers/container_layer.h"
+#include "third_party/skia/include/core/SkPath.h"
 
 namespace flutter {
 
 class ClipPathLayer : public ContainerLayer {
  public:
   ClipPathLayer(const SkPath& clip_path, Clip clip_behavior = Clip::antiAlias);
+  ~ClipPathLayer() override;
 
   void Preroll(PrerollContext* context, const SkMatrix& matrix) override;
-
   void Paint(PaintContext& context) const override;
 
   bool UsesSaveLayer() const {

flow/layers/clip_path_layer_unittests.cc

@@ -218,7 +218,7 @@ TEST_F(ClipPathLayerTest, Readback) {
   const Clip save_layer = Clip::antiAliasWithSaveLayer;
 
   std::shared_ptr<MockLayer> nochild;
-  auto reader = std::make_shared<MockLayer>(path, paint, false, false, true);
+  auto reader = std::make_shared<MockLayer>(path, paint, false, true);
   auto nonreader = std::make_shared<MockLayer>(path, paint);
 
   // No children, no prior readback -> no readback after

flow/layers/clip_rect_layer.cc

@@ -11,6 +11,8 @@ ClipRectLayer::ClipRectLayer(const SkRect& clip_rect, Clip clip_behavior)
   FML_DCHECK(clip_behavior != Clip::none);
 }
 
+ClipRectLayer::~ClipRectLayer() = default;
+
 void ClipRectLayer::Preroll(PrerollContext* context, const SkMatrix& matrix) {
   TRACE_EVENT0("flutter", "ClipRectLayer::Preroll");
 
@@ -22,30 +24,17 @@ void ClipRectLayer::Preroll(PrerollContext* context, const SkMatrix& matrix) {
     Layer::AutoPrerollSaveLayerState save =
         Layer::AutoPrerollSaveLayerState::Create(context, UsesSaveLayer());
     context->mutators_stack.PushClipRect(clip_rect_);
-    SkRect child_paint_bounds = SkRect::MakeEmpty();
-    PrerollChildren(context, matrix, &child_paint_bounds);
+    ContainerLayer::Preroll(context, matrix);
 
-    if (child_paint_bounds.intersect(clip_rect_)) {
-      set_paint_bounds(child_paint_bounds);
+    SkRect new_paint_bounds;
+    if (new_paint_bounds.intersect(paint_bounds(), clip_rect_)) {
+      set_paint_bounds(new_paint_bounds);
     }
     context->mutators_stack.Pop();
   }
   context->cull_rect = previous_cull_rect;
 }
 
-#if defined(LEGACY_FUCHSIA_EMBEDDER)
-
-void ClipRectLayer::UpdateScene(SceneUpdateContext& context) {
-  TRACE_EVENT0("flutter", "ClipRectLayer::UpdateScene");
-  FML_DCHECK(needs_system_composite());
-
-  // TODO(liyuqian): respect clip_behavior_
-  SceneUpdateContext::Clip clip(context, clip_rect_);
-  UpdateSceneChildren(context);
-}
-
-#endif
-
 void ClipRectLayer::Paint(PaintContext& context) const {
   TRACE_EVENT0("flutter", "ClipRectLayer::Paint");
   FML_DCHECK(needs_painting());
@@ -62,10 +51,23 @@ void ClipRectLayer::Paint(PaintContext& context) const {
   if (UsesSaveLayer()) {
     context.internal_nodes_canvas->saveLayer(clip_rect_, nullptr);
   }
-  PaintChildren(context);
+  ContainerLayer::Paint(context);
   if (UsesSaveLayer()) {
     context.internal_nodes_canvas->restore();
   }
 }
 
+#if defined(LEGACY_FUCHSIA_EMBEDDER)
+
+void ClipRectLayer::UpdateScene(SceneUpdateContext& context) {
+  TRACE_EVENT0("flutter", "ClipRectLayer::UpdateScene");
+  FML_DCHECK(needs_system_composite());
+
+  // TODO(liyuqian): respect clip_behavior_
+  SceneUpdateContext::Clip clip(context, clip_rect_);
+  ContainerLayer::UpdateScene(context);
+}
+
+#endif
+
 }  // namespace flutter

flow/layers/clip_rect_layer.h

@@ -7,11 +7,14 @@
 
 #include "flutter/flow/layers/container_layer.h"
 
+#include "third_party/skia/include/core/SkRect.h"
+
 namespace flutter {
 
 class ClipRectLayer : public ContainerLayer {
  public:
   ClipRectLayer(const SkRect& clip_rect, Clip clip_behavior);
+  ~ClipRectLayer() override;
 
   void Preroll(PrerollContext* context, const SkMatrix& matrix) override;
   void Paint(PaintContext& context) const override;

flow/layers/clip_rect_layer_unittests.cc

@@ -215,7 +215,7 @@ TEST_F(ClipRectLayerTest, Readback) {
   const Clip save_layer = Clip::antiAliasWithSaveLayer;
 
   std::shared_ptr<MockLayer> nochild;
-  auto reader = std::make_shared<MockLayer>(path, paint, false, false, true);
+  auto reader = std::make_shared<MockLayer>(path, paint, false, true);
   auto nonreader = std::make_shared<MockLayer>(path, paint);
 
   // No children, no prior readback -> no readback after