Cleanup: Mark some overridden methods with 'SK_OVERRIDE'.

src/gpu/effects/GrYUVtoRGBEffect.cpp

Index: src/gpu/effects/GrYUVtoRGBEffect.cpp
diff --git a/src/gpu/effects/GrYUVtoRGBEffect.cpp b/src/gpu/effects/GrYUVtoRGBEffect.cpp
index 50d0e52d6e8a20719269526e19397f9e9387b1d4..e8c7ff7acafb93d8bf704729647a956d63a5057f 100644
--- a/src/gpu/effects/GrYUVtoRGBEffect.cpp
+++ b/src/gpu/effects/GrYUVtoRGBEffect.cpp
@@ -104,7 +104,7 @@ private:
         this->addTextureAccess(&fVAccess);
     }
 
-    virtual bool onIsEqual(const GrFragmentProcessor& sBase) const {
+    virtual bool onIsEqual(const GrFragmentProcessor& sBase) const SK_OVERRIDE {
         const YUVtoRGBEffect& s = sBase.cast<YUVtoRGBEffect>();
         return fColorSpace == s.getColorSpace();
     }