Add NV12 texture conversion support.

include/core/SkImage.h

Index: include/core/SkImage.h
diff --git a/include/core/SkImage.h b/include/core/SkImage.h
index 50a9f5761267c200442233063d5136257f28c94c..52a2bf7af76674125225ab82f17a4b84b169debd 100644
--- a/include/core/SkImage.h
+++ b/include/core/SkImage.h
@@ -138,6 +138,15 @@ public:
                                                   const SkISize yuvSizes[3],
                                                   GrSurfaceOrigin);
 
+    /**
+     *  Create a new image by copying the pixels from the specified y and uv textures. The data
+     *  from the textures is immediately ingested into the image and the textures can be modified or
+     *  deleted after the function returns. The image will have the dimensions of the y texture.
+     */
+    static sk_sp<SkImage> MakeFromNV12TexturesCopy(GrContext*, SkYUVColorSpace,
+                                                   const GrBackendObject nv12TextureHandles[2],
+                                                   const SkISize nv12Sizes[2], GrSurfaceOrigin);
+
     static sk_sp<SkImage> MakeFromPicture(sk_sp<SkPicture>, const SkISize& dimensions,
                                           const SkMatrix*, const SkPaint*);