Clean up Skia includes around SkSurfaceCharacterization (flutter#42485)

While contemplating a change to SkSurfaceCharacterization, I was curious
who was using this. Flutter #included it, but never actually seemed to
use it. Thus, I removed includes of it and other unnecessary #includes
in those same files, as well as addressing follow-on compile errors.

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there for submitting PRs.
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responsibilities.
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Objective-C, Java style guides].
- [ ] I listed at least one issue that this PR fixes in the description
above.
- [x] I added new tests to check the change I am making or feature I am
adding, or Hixie said the PR is test-exempt. See [testing the engine]
for instructions on writing and running engine tests.
- [ ] I updated/added relevant documentation (doc comments with `///`).
- [x] I signed the [CLA].
- [x] All existing and new tests are passing.

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flow/layer_snapshot_store.h

@@ -11,13 +11,8 @@
 #include "flutter/fml/time/time_delta.h"
 
 #include "third_party/skia/include/core/SkData.h"
-#include "third_party/skia/include/core/SkPictureRecorder.h"
 #include "third_party/skia/include/core/SkRect.h"
 #include "third_party/skia/include/core/SkRefCnt.h"
-#include "third_party/skia/include/core/SkSerialProcs.h"
-#include "third_party/skia/include/core/SkSurface.h"
-#include "third_party/skia/include/core/SkSurfaceCharacterization.h"
-#include "third_party/skia/include/utils/SkBase64.h"
 
 namespace flutter {
 

flow/layers/offscreen_surface.cc

@@ -5,15 +5,13 @@
 #include "flutter/flow/layers/offscreen_surface.h"
 
 #include "third_party/skia/include/core/SkColorSpace.h"
+#include "third_party/skia/include/core/SkData.h"
 #include "third_party/skia/include/core/SkImage.h"
 #include "third_party/skia/include/core/SkImageInfo.h"
-#include "third_party/skia/include/core/SkPictureRecorder.h"
 #include "third_party/skia/include/core/SkPixmap.h"
-#include "third_party/skia/include/core/SkSerialProcs.h"
-#include "third_party/skia/include/core/SkSurfaceCharacterization.h"
 #include "third_party/skia/include/encode/SkPngEncoder.h"
+#include "third_party/skia/include/gpu/GrDirectContext.h"
 #include "third_party/skia/include/gpu/ganesh/SkSurfaceGanesh.h"
-#include "third_party/skia/include/utils/SkBase64.h"
 
 namespace flutter {
 
@@ -24,9 +22,8 @@ static sk_sp<SkSurface> CreateSnapshotSurface(GrDirectContext* surface_context,
   if (surface_context) {
     // There is a rendering surface that may contain textures that are going to
     // be referenced in the layer tree about to be drawn.
-    return SkSurfaces::RenderTarget(
-        reinterpret_cast<GrRecordingContext*>(surface_context),
-        skgpu::Budgeted::kNo, image_info);
+    return SkSurfaces::RenderTarget(surface_context, skgpu::Budgeted::kNo,
+                                    image_info);
   }
 
   // There is no rendering surface, assume no GPU textures are present and

flow/testing/mock_raster_cache.h

@@ -11,7 +11,9 @@
 #include "flutter/flow/raster_cache_item.h"
 #include "flutter/flow/testing/mock_layer.h"
 #include "flutter/testing/mock_canvas.h"
-#include "third_party/skia/include/core/SkImage.h"
+#include "third_party/skia/include/core/SkColorSpace.h"
+#include "third_party/skia/include/core/SkRefCnt.h"
+#include "third_party/skia/include/core/SkSize.h"
 
 namespace flutter {
 namespace testing {

shell/common/rasterizer.cc

@@ -15,13 +15,17 @@
 #include "flutter/fml/time/time_point.h"
 #include "flutter/shell/common/serialization_callbacks.h"
 #include "fml/make_copyable.h"
+#include "third_party/skia/include/core/SkColorSpace.h"
+#include "third_party/skia/include/core/SkData.h"
+#include "third_party/skia/include/core/SkImage.h"
 #include "third_party/skia/include/core/SkImageInfo.h"
 #include "third_party/skia/include/core/SkMatrix.h"
 #include "third_party/skia/include/core/SkPictureRecorder.h"
+#include "third_party/skia/include/core/SkRect.h"
 #include "third_party/skia/include/core/SkSerialProcs.h"
 #include "third_party/skia/include/core/SkSize.h"
 #include "third_party/skia/include/core/SkSurface.h"
-#include "third_party/skia/include/core/SkSurfaceCharacterization.h"
+#include "third_party/skia/include/gpu/GrDirectContext.h"
 #include "third_party/skia/include/gpu/ganesh/SkSurfaceGanesh.h"
 #include "third_party/skia/include/utils/SkBase64.h"
 

shell/common/rasterizer_unittests.cc

@@ -15,6 +15,7 @@
 #include "flutter/shell/common/thread_host.h"
 #include "flutter/testing/testing.h"
 
+#include "third_party/skia/include/core/SkColorSpace.h"
 #include "third_party/skia/include/core/SkSurface.h"
 #include "third_party/skia/include/gpu/ganesh/SkSurfaceGanesh.h"
 

shell/platform/embedder/pixel_formats.cc

@@ -5,6 +5,10 @@
 #include "flutter/shell/platform/embedder/pixel_formats.h"
 #include "flutter/shell/platform/embedder/embedder.h"
 
+#include "third_party/skia/include/core/SkColorSpace.h"
+#include "third_party/skia/include/core/SkColorType.h"
+#include "third_party/skia/include/core/SkImageInfo.h"
+
 std::optional<SkColorType> getSkColorType(FlutterSoftwarePixelFormat pixfmt) {
   switch (pixfmt) {
     case kFlutterSoftwarePixelFormatGray8: