Move willUseInputColor check to computeInvariantOutput

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 e3d25a2f1d456119ec6049fd5c4242e5080f7d74..c973bcfc637f14d57deb490b39fffcf00e459f62 100644
--- a/src/gpu/effects/GrYUVtoRGBEffect.cpp
+++ b/src/gpu/effects/GrYUVtoRGBEffect.cpp
@@ -99,7 +99,6 @@ private:
         this->addTextureAccess(&fYAccess);
         this->addTextureAccess(&fUAccess);
         this->addTextureAccess(&fVAccess);
-        this->setWillNotUseInputColor();
     }
 
     virtual bool onIsEqual(const GrProcessor& sBase) const {
@@ -113,6 +112,7 @@ private:
     virtual void onComputeInvariantOutput(InvariantOutput* inout) const SK_OVERRIDE {
         // YUV is opaque
         inout->setToOther(kA_GrColorComponentFlag, 0xFF << GrColor_SHIFT_A);
+        inout->setWillNotUseInputColor();
     }
 
     GrCoordTransform fCoordTransform;