Pin color type when a cross-context image is constructed

Fixes issues with gray images that may be incorrectly re-interpreted as
alpha when re-wrapped. (https://github.com/flutter/flutter/issues/15600)

Change-Id: I4a78466073e14d212108d168eed0b2df1bc92ffe
Reviewed-on: https://skia-review.googlesource.com/116484
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>

3 files changed, 14 insertions, 9 deletions

diff --git a/src/gpu/GrBackendTextureImageGenerator.cpp b/src/gpu/GrBackendTextureImageGenerator.cpp
index 73f19b0199..90a251865a 100644
--- a/src/gpu/GrBackendTextureImageGenerator.cpp
+++ b/src/gpu/GrBackendTextureImageGenerator.cpp
@@ -33,13 +33,8 @@ GrBackendTextureImageGenerator::RefHelper::~RefHelper() {
 
 std::unique_ptr<SkImageGenerator>
 GrBackendTextureImageGenerator::Make(sk_sp<GrTexture> texture, GrSurfaceOrigin origin,
-                                     sk_sp<GrSemaphore> semaphore,
+                                     sk_sp<GrSemaphore> semaphore, SkColorType colorType,
                                      SkAlphaType alphaType, sk_sp<SkColorSpace> colorSpace) {
-    SkColorType colorType = kUnknown_SkColorType;
-    if (!GrPixelConfigToColorType(texture->config(), &colorType)) {
-        return nullptr;
-    }
-
     GrContext* context = texture->getContext();
 
     // Attach our texture to this context's resource cache. This ensures that deletion will happen
@@ -48,6 +43,10 @@ GrBackendTextureImageGenerator::Make(sk_sp<GrTexture> texture, GrSurfaceOrigin o
     context->contextPriv().getResourceCache()->insertCrossContextGpuResource(texture.get());
 
     GrBackendTexture backendTexture = texture->getBackendTexture();
+    if (!context->caps()->validateBackendTexture(backendTexture, colorType,
+                                                 &backendTexture.fConfig)) {
+        return nullptr;
+    }
 
     SkImageInfo info = SkImageInfo::Make(texture->width(), texture->height(), colorType, alphaType,
                                          std::move(colorSpace));
@@ -93,6 +92,9 @@ sk_sp<GrTextureProxy> GrBackendTextureImageGenerator::onGenerateTexture(
     if (context->contextPriv().getBackend() != fBackendTexture.backend()) {
         return nullptr;
     }
+    if (info.colorType() != this->getInfo().colorType()) {
+        return nullptr;
+    }
 
     auto proxyProvider = context->contextPriv().proxyProvider();
 
diff --git a/src/gpu/GrBackendTextureImageGenerator.h b/src/gpu/GrBackendTextureImageGenerator.h
index 59f0d510da..5197d32273 100644
--- a/src/gpu/GrBackendTextureImageGenerator.h
+++ b/src/gpu/GrBackendTextureImageGenerator.h
@@ -29,7 +29,7 @@ class GrSemaphore;
 class GrBackendTextureImageGenerator : public SkImageGenerator {
 public:
     static std::unique_ptr<SkImageGenerator> Make(sk_sp<GrTexture>, GrSurfaceOrigin,
-                                                  sk_sp<GrSemaphore>,
+                                                  sk_sp<GrSemaphore>, SkColorType,
                                                   SkAlphaType, sk_sp<SkColorSpace>);
 
     ~GrBackendTextureImageGenerator() override;
diff --git a/src/image/SkImage_Gpu.cpp b/src/image/SkImage_Gpu.cpp
index 4733cae06e..3c05f1d219 100644
--- a/src/image/SkImage_Gpu.cpp
+++ b/src/image/SkImage_Gpu.cpp
@@ -723,7 +723,9 @@ sk_sp<SkImage> SkImage::MakeCrossContextFromEncoded(GrContext* context, sk_sp<Sk
     sk_sp<GrSemaphore> sema = gpu->prepareTextureForCrossContextUsage(texture.get());
 
     auto gen = GrBackendTextureImageGenerator::Make(std::move(texture), proxy->origin(),
-                                                    std::move(sema), codecImage->alphaType(),
+                                                    std::move(sema),
+                                                    as_IB(codecImage)->onImageInfo().colorType(),
+                                                    codecImage->alphaType(),
                                                     std::move(texColorSpace));
     return SkImage::MakeFromGenerator(std::move(gen));
 }
@@ -778,7 +780,8 @@ sk_sp<SkImage> SkImage::MakeCrossContextFromPixmap(GrContext* context, const SkP
     sk_sp<GrSemaphore> sema = gpu->prepareTextureForCrossContextUsage(texture.get());
 
     auto gen = GrBackendTextureImageGenerator::Make(std::move(texture), proxy->origin(),
-                                                    std::move(sema), pixmap.alphaType(),
+                                                    std::move(sema), pixmap.colorType(),
+                                                    pixmap.alphaType(),
                                                     pixmap.info().refColorSpace());
     return SkImage::MakeFromGenerator(std::move(gen));
 }