[impeller] fake image for fake tests. (#54974)

Simulator only change to allow toImage and toByteData to not fail when there is no metal context w/ impeller.

Author: Jonah Williams

display_list/image/dl_image.h

@@ -9,7 +9,7 @@
 #include <optional>
 #include <string>
 
-#include "flutter/fml/macros.h"
+#include "flutter/fml/build_config.h"
 #include "third_party/skia/include/core/SkImage.h"
 #include "third_party/skia/include/core/SkRefCnt.h"
 
@@ -118,6 +118,10 @@ class DlImage : public SkRefCnt {
   ///             image.
   virtual std::optional<std::string> get_error() const;
 
+#if FML_OS_IOS_SIMULATOR
+  virtual bool IsFakeImage() const { return false; }
+#endif  // FML_OS_IOS_SIMULATOR
+
   bool Equals(const DlImage* other) const {
     if (!other) {
       return false;

impeller/display_list/dl_image_impeller.cc

@@ -9,6 +9,17 @@
 
 namespace impeller {
 
+#if FML_OS_IOS_SIMULATOR
+sk_sp<DlImageImpeller> DlImageImpeller::Make(std::shared_ptr<Texture> texture,
+                                             OwningContext owning_context,
+                                             bool is_fake_image) {
+  if (!texture && !is_fake_image) {
+    return nullptr;
+  }
+  return sk_sp<DlImageImpeller>(
+      new DlImageImpeller(std::move(texture), owning_context, is_fake_image));
+}
+#else
 sk_sp<DlImageImpeller> DlImageImpeller::Make(std::shared_ptr<Texture> texture,
                                              OwningContext owning_context) {
   if (!texture) {
@@ -17,6 +28,7 @@ sk_sp<DlImageImpeller> DlImageImpeller::Make(std::shared_ptr<Texture> texture,
   return sk_sp<DlImageImpeller>(
       new DlImageImpeller(std::move(texture), owning_context));
 }
+#endif  // FML_OS_IOS_SIMULATOR
 
 sk_sp<DlImageImpeller> DlImageImpeller::MakeFromYUVTextures(
     AiksContext* aiks_context,
@@ -45,8 +57,20 @@ sk_sp<DlImageImpeller> DlImageImpeller::MakeFromYUVTextures(
 }
 
 DlImageImpeller::DlImageImpeller(std::shared_ptr<Texture> texture,
-                                 OwningContext owning_context)
-    : texture_(std::move(texture)), owning_context_(owning_context) {}
+                                 OwningContext owning_context
+#ifdef FML_OS_IOS_SIMULATOR
+                                 ,
+                                 bool is_fake_image
+#endif  // FML_OS_IOS_SIMULATOR
+                                 )
+    : texture_(std::move(texture)),
+      owning_context_(owning_context)
+#ifdef FML_OS_IOS_SIMULATOR
+      ,
+      is_fake_image_(is_fake_image)
+#endif  // #ifdef FML_OS_IOS_SIMULATOR
+{
+}
 
 // |DlImage|
 DlImageImpeller::~DlImageImpeller() = default;

impeller/display_list/dl_image_impeller.h

@@ -16,7 +16,12 @@ class DlImageImpeller final : public flutter::DlImage {
  public:
   static sk_sp<DlImageImpeller> Make(
       std::shared_ptr<Texture> texture,
-      OwningContext owning_context = OwningContext::kIO);
+      OwningContext owning_context = OwningContext::kIO
+#if FML_OS_IOS_SIMULATOR
+      ,
+      bool is_fake_image = false
+#endif  // FML_OS_IOS_SIMULATOR
+  );
 
   static sk_sp<DlImageImpeller> MakeFromYUVTextures(
       AiksContext* aiks_context,
@@ -51,12 +56,25 @@ class DlImageImpeller final : public flutter::DlImage {
   // |DlImage|
   OwningContext owning_context() const override { return owning_context_; }
 
+#if FML_OS_IOS_SIMULATOR
+  // |DlImage|
+  bool IsFakeImage() const override { return is_fake_image_; }
+#endif  // FML_OS_IOS_SIMULATOR
+
  private:
   std::shared_ptr<Texture> texture_;
   OwningContext owning_context_;
+#if FML_OS_IOS_SIMULATOR
+  bool is_fake_image_ = false;
+#endif  // FML_OS_IOS_SIMULATOR
 
   explicit DlImageImpeller(std::shared_ptr<Texture> texture,
-                           OwningContext owning_context = OwningContext::kIO);
+                           OwningContext owning_context = OwningContext::kIO
+#if FML_OS_IOS_SIMULATOR
+                           ,
+                           bool is_fake_image = false
+#endif  // FML_OS_IOS_SIMULATOR
+  );
 
   DlImageImpeller(const DlImageImpeller&) = delete;
 

lib/ui/painting/image.cc

@@ -52,8 +52,7 @@ int CanvasImage::colorSpace() {
     return ImageEncodingImpeller::GetColorSpace(image_->impeller_texture());
 #endif  // IMPELLER_SUPPORTS_RENDERING
   }
-
-  return -1;
+  return ColorSpace::kSRGB;
 }
 
 }  // namespace flutter

lib/ui/painting/image_encoding.cc

@@ -178,6 +178,14 @@ Dart_Handle EncodeImage(CanvasImage* canvas_image,
   auto callback = std::make_unique<DartPersistentValue>(
       tonic::DartState::Current(), callback_handle);
 
+#if IMPELLER_SUPPORTS_RENDERING && FML_OS_IOS_SIMULATOR
+  if (canvas_image->image()->IsFakeImage()) {
+    sk_sp<SkData> data = SkData::MakeEmpty();
+    InvokeDataCallback(std::move(callback), data);
+    return Dart_Null();
+  }
+#endif  // IMPELLER_SUPPORTS_RENDERING && FML_OS_IOS_SIMULATOR
+
   const auto& task_runners = UIDartState::Current()->GetTaskRunners();
 
   // The static leak checker gets confused by the use of fml::MakeCopyable.

lib/ui/painting/picture.cc

@@ -207,7 +207,6 @@ Dart_Handle Picture::DoRasterizeToImage(const sk_sp<DisplayList>& display_list,
                          height, ui_task,
                          layer_tree = std::move(layer_tree)]() mutable {
         auto picture_bounds = SkISize::Make(width, height);
-        sk_sp<DlImage> image;
         sk_sp<DisplayList> snapshot_display_list = display_list;
         if (layer_tree) {
           FML_DCHECK(picture_bounds == layer_tree->frame_size());

shell/common/snapshot_controller_impeller.cc

@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include "flutter/flow/surface.h"
+#include "flutter/fml/build_config.h"
 #include "flutter/fml/trace_event.h"
 #include "flutter/impeller/display_list/dl_dispatcher.h"
 #include "flutter/impeller/display_list/dl_image_impeller.h"
@@ -126,7 +127,6 @@ void SnapshotControllerImpeller::MakeRasterSnapshot(
     sk_sp<DisplayList> display_list,
     SkISize picture_size,
     std::function<void(const sk_sp<DlImage>&)> callback) {
-  sk_sp<DlImage> result;
   std::shared_ptr<const fml::SyncSwitch> sync_switch =
       GetDelegate().GetIsGpuDisabledSyncSwitch();
   sync_switch->Execute(
@@ -143,10 +143,25 @@ void SnapshotControllerImpeller::MakeRasterSnapshot(
                   },
                   [callback]() { callback(nullptr); });
             } else {
+#if FML_OS_IOS_SIMULATOR
+              callback(impeller::DlImageImpeller::Make(
+                  nullptr, DlImage::OwningContext::kRaster,
+                  /*is_fake_image=*/true));
+#else
               callback(nullptr);
+
+#endif  // FML_OS_IOS_SIMULATOR
             }
           })
           .SetIfFalse([&] {
+#if FML_OS_IOS_SIMULATOR
+            if (!GetDelegate().GetAiksContext()) {
+              callback(impeller::DlImageImpeller::Make(
+                  nullptr, DlImage::OwningContext::kRaster,
+                  /*is_fake_image=*/true));
+              return;
+            }
+#endif
             callback(DoMakeRasterSnapshot(display_list, picture_size,
                                           GetDelegate().GetAiksContext()));
           }));