Add alpha type to texture producer

src/image/SkImage_Gpu.cpp

Index: src/image/SkImage_Gpu.cpp
diff --git a/src/image/SkImage_Gpu.cpp b/src/image/SkImage_Gpu.cpp
index eba66f46ed91146d6faa4a8e7e67697fa6215de5..6b7416b26bf31cc4e19eeba9d1615f5f67e05a79 100644
--- a/src/image/SkImage_Gpu.cpp
+++ b/src/image/SkImage_Gpu.cpp
@@ -82,7 +82,7 @@ bool SkImage_Gpu::getROPixels(SkBitmap* dst, CachingHint chint) const {
 
 GrTexture* SkImage_Gpu::asTextureRef(GrContext* ctx, const GrTextureParams& params,
                                      SkSourceGammaTreatment gammaTreatment) const {
-    GrTextureAdjuster adjuster(this->peekTexture(), this->bounds(), this->uniqueID(),
+    GrTextureAdjuster adjuster(this->peekTexture(), this->alphaType(), this->bounds(), this->uniqueID(),
                                this->onImageInfo().colorSpace());
     return adjuster.refTextureSafeForParams(params, gammaTreatment, nullptr);
 }