Skia side RGB to YUV gpu conversion

src/lazy/SkDiscardablePixelRef.h

Index: src/lazy/SkDiscardablePixelRef.h
diff --git a/src/lazy/SkDiscardablePixelRef.h b/src/lazy/SkDiscardablePixelRef.h
index 2edef80128f0bb8a8e88de4001a2d0715f2b3cdb..d31a040164846d4af0780f0bac64b7c24c3326ca 100644
--- a/src/lazy/SkDiscardablePixelRef.h
+++ b/src/lazy/SkDiscardablePixelRef.h
@@ -48,6 +48,12 @@ private:
                           size_t rowBytes,
                           SkDiscardableMemory::Factory* factory);
 
+    virtual bool onGetYUV8Planes(SkISize sizes[3],
+                                 void* planes[3],
+                                 size_t rowBytes[3]) SK_OVERRIDE {
+        return fGenerator->getYUV8Planes(sizes, planes, rowBytes);
+    }
+
     friend bool SkInstallDiscardablePixelRef(SkImageGenerator*, SkBitmap*,
                                              SkDiscardableMemory::Factory*);