[scene_host] Expose Opacity and remove ExportNode

ci/licenses_golden/licenses_flutter

@@ -30,8 +30,6 @@ FILE: ../../../flutter/flow/debug_print.cc
 FILE: ../../../flutter/flow/debug_print.h
 FILE: ../../../flutter/flow/embedded_views.cc
 FILE: ../../../flutter/flow/embedded_views.h
-FILE: ../../../flutter/flow/export_node.cc
-FILE: ../../../flutter/flow/export_node.h
 FILE: ../../../flutter/flow/instrumentation.cc
 FILE: ../../../flutter/flow/instrumentation.h
 FILE: ../../../flutter/flow/layers/backdrop_filter_layer.cc

flow/BUILD.gn

@@ -76,8 +76,6 @@ source_set("flow") {
 
   if (is_fuchsia) {
     sources += [
-      "export_node.cc",
-      "export_node.h",
       "layers/child_scene_layer.cc",
       "layers/child_scene_layer.h",
       "scene_update_context.cc",

flow/layers/child_scene_layer.cc

@@ -4,21 +4,18 @@
 
 #include "flutter/flow/layers/child_scene_layer.h"
 
-#include "flutter/flow/export_node.h"
 #include "flutter/flow/view_holder.h"
 
 namespace flutter {
 
 ChildSceneLayer::ChildSceneLayer(zx_koid_t layer_id,
-                                 bool use_view_holder,
                                  const SkPoint& offset,
                                  const SkSize& size,
                                  bool hit_testable)
     : layer_id_(layer_id),
       offset_(offset),
       size_(size),
-      hit_testable_(hit_testable),
-      use_view_holder_(use_view_holder) {}
+      hit_testable_(hit_testable) {}
 
 void ChildSceneLayer::Preroll(PrerollContext* context, const SkMatrix& matrix) {
   set_needs_system_composite(true);
@@ -31,17 +28,10 @@ void ChildSceneLayer::Paint(PaintContext& context) const {
 void ChildSceneLayer::UpdateScene(SceneUpdateContext& context) {
   FML_DCHECK(needs_system_composite());
 
-  if (use_view_holder_) {
-    auto* view_holder = ViewHolder::FromId(layer_id_);
-    FML_DCHECK(view_holder);
+  auto* view_holder = ViewHolder::FromId(layer_id_);
+  FML_DCHECK(view_holder);
 
-    view_holder->UpdateScene(context, offset_, size_, hit_testable_);
-  } else {
-    auto* export_node = ExportNode::FromId(layer_id_);
-    FML_DCHECK(export_node);
-
-    export_node->UpdateScene(context, offset_, size_, hit_testable_);
-  }
+  view_holder->UpdateScene(context, offset_, size_, hit_testable_);
 }
 
 }  // namespace flutter

flow/layers/child_scene_layer.h

@@ -18,7 +18,6 @@ namespace flutter {
 class ChildSceneLayer : public Layer {
  public:
   ChildSceneLayer(zx_koid_t layer_id,
-                  bool use_view_holder,
                   const SkPoint& offset,
                   const SkSize& size,
                   bool hit_testable);
@@ -35,7 +34,6 @@ class ChildSceneLayer : public Layer {
   SkPoint offset_;
   SkSize size_;
   bool hit_testable_ = true;
-  bool use_view_holder_ = true;
 
   FML_DISALLOW_COPY_AND_ASSIGN(ChildSceneLayer);
 };

flow/view_holder.cc

@@ -48,16 +48,6 @@ fuchsia::ui::gfx::ViewProperties ToViewProperties(float width,
 
 namespace flutter {
 
-ViewHolder::ViewHolder(fml::RefPtr<fml::TaskRunner> ui_task_runner,
-                       fuchsia::ui::views::ViewHolderToken view_holder_token,
-                       BindCallback on_bind_callback)
-    : pending_view_holder_token_(std::move(view_holder_token)),
-      ui_task_runner_(std::move(ui_task_runner)),
-      pending_bind_callback_(std::move(on_bind_callback)) {
-  FML_DCHECK(pending_view_holder_token_.value);
-  FML_DCHECK(ui_task_runner_);
-}
-
 void ViewHolder::Create(zx_koid_t id,
                         fml::RefPtr<fml::TaskRunner> ui_task_runner,
                         fuchsia::ui::views::ViewHolderToken view_holder_token,
@@ -72,9 +62,9 @@ void ViewHolder::Create(zx_koid_t id,
   FML_DCHECK(bindings);
   FML_DCHECK(bindings->find(id) == bindings->end());
 
-  auto view_holder = std::unique_ptr<ViewHolder>(
-      new ViewHolder(std::move(ui_task_runner), std::move(view_holder_token),
-                     std::move(on_bind_callback)));
+  auto view_holder = std::make_unique<ViewHolder>(std::move(ui_task_runner),
+                                                  std::move(view_holder_token),
+                                                  std::move(on_bind_callback));
   bindings->emplace(id, std::move(view_holder));
 }
 
@@ -99,31 +89,49 @@ ViewHolder* ViewHolder::FromId(zx_koid_t id) {
   return binding->second.get();
 }
 
+ViewHolder::ViewHolder(fml::RefPtr<fml::TaskRunner> ui_task_runner,
+                       fuchsia::ui::views::ViewHolderToken view_holder_token,
+                       BindCallback on_bind_callback)
+    : ui_task_runner_(std::move(ui_task_runner)),
+      pending_view_holder_token_(std::move(view_holder_token)),
+      pending_bind_callback_(std::move(on_bind_callback)) {
+  FML_DCHECK(ui_task_runner_);
+  FML_DCHECK(pending_view_holder_token_.value);
+}
+
 void ViewHolder::UpdateScene(SceneUpdateContext& context,
                              const SkPoint& offset,
                              const SkSize& size,
                              bool hit_testable) {
   if (pending_view_holder_token_.value) {
+    opacity_node_ =
+        std::make_unique<scenic::OpacityNodeHACK>(context.session());
     entity_node_ = std::make_unique<scenic::EntityNode>(context.session());
     view_holder_ = std::make_unique<scenic::ViewHolder>(
         context.session(), std::move(pending_view_holder_token_),
         "Flutter SceneHost");
 
+    opacity_node_->AddChild(*entity_node_);
     entity_node_->Attach(*view_holder_);
     ui_task_runner_->PostTask(
         [bind_callback = std::move(pending_bind_callback_),
          view_holder_id = view_holder_->id()]() {
           bind_callback(view_holder_id);
         });
   }
-  FML_DCHECK(entity_node_);
+  FML_DCHECK(opacity_node_);
   FML_DCHECK(view_holder_);
 
-  context.top_entity()->entity_node().AddChild(*entity_node_);
+  context.top_entity()->entity_node().AddChild(*opacity_node_);
   entity_node_->SetTranslation(offset.x(), offset.y(), -0.1f);
   entity_node_->SetHitTestBehavior(
       hit_testable ? fuchsia::ui::gfx::HitTestBehavior::kDefault
                    : fuchsia::ui::gfx::HitTestBehavior::kSuppress);
+  if (has_pending_opacity_) {
+    opacity_node_->SetOpacity(pending_opacity_);
+
+    has_pending_opacity_ = false;
+  }
   if (has_pending_properties_) {
     view_holder_->SetViewProperties(std::move(pending_properties_));
 
@@ -143,4 +151,9 @@ void ViewHolder::SetProperties(double width,
   has_pending_properties_ = true;
 }
 
+void ViewHolder::SetOpacity(double opacity) {
+  pending_opacity_ = std::clamp(opacity, 0.0, 1.0);
+  has_pending_opacity_ = true;
+}
+
 }  // namespace flutter

flow/view_holder.h

@@ -38,14 +38,20 @@ class ViewHolder {
   static void Destroy(zx_koid_t id);
   static ViewHolder* FromId(zx_koid_t id);
 
-  // Sets the properties of the child view by issuing a Scenic command.
+  ViewHolder(fml::RefPtr<fml::TaskRunner> ui_task_runner,
+             fuchsia::ui::views::ViewHolderToken view_holder_token,
+             BindCallback on_bind_callback);
+  ~ViewHolder() = default;
+
+  // Sets the properties/opacity of the child view by issuing a Scenic command.
   void SetProperties(double width,
                      double height,
                      double insetTop,
                      double insetRight,
                      double insetBottom,
                      double insetLeft,
                      bool focusable);
+  void SetOpacity(double opacity);
 
   // Creates or updates the contained ViewHolder resource using the specified
   // |SceneUpdateContext|.
@@ -55,17 +61,19 @@ class ViewHolder {
                    bool hit_testable);
 
  private:
-  ViewHolder(fml::RefPtr<fml::TaskRunner> ui_task_runner,
-             fuchsia::ui::views::ViewHolderToken view_holder_token,
-             BindCallback on_bind_callback);
-
-  fuchsia::ui::gfx::ViewProperties pending_properties_;
-  fuchsia::ui::views::ViewHolderToken pending_view_holder_token_;
   fml::RefPtr<fml::TaskRunner> ui_task_runner_;
+
+  std::unique_ptr<scenic::OpacityNodeHACK> opacity_node_;
   std::unique_ptr<scenic::EntityNode> entity_node_;
   std::unique_ptr<scenic::ViewHolder> view_holder_;
+
+  fuchsia::ui::views::ViewHolderToken pending_view_holder_token_;
   BindCallback pending_bind_callback_;
+
+  fuchsia::ui::gfx::ViewProperties pending_properties_;
+  double pending_opacity_;
   bool has_pending_properties_ = false;
+  bool has_pending_opacity_ = false;
 
   FML_DISALLOW_COPY_AND_ASSIGN(ViewHolder);
 };