Move willUseInputColor check to computeInvariantOutput

src/effects/SkColorMatrixFilter.cpp

Index: src/effects/SkColorMatrixFilter.cpp
diff --git a/src/effects/SkColorMatrixFilter.cpp b/src/effects/SkColorMatrixFilter.cpp
index 4aee11aa5b16ab717cf37e439decabc0041d5431..844a37638cb39626a3c6174e03a77f2a9d5ec0eb 100644
--- a/src/effects/SkColorMatrixFilter.cpp
+++ b/src/effects/SkColorMatrixFilter.cpp
@@ -453,7 +453,7 @@ private:
             // then we can't know the final result.
             if (0 != fMatrix.fMat[kAlphaRowStartIdx + i]) {
                 if (!(inout->validFlags() & kRGBAFlags[i])) {
-                    inout->setToUnknown();
+                    inout->setToUnknown(InvariantOutput::kWill_ReadInput);
                     return;
                 } else {
                     uint32_t component = (inout->color() >> kShifts[i]) & 0xFF;
@@ -467,7 +467,8 @@ private:
         // underflow this may deviate from the actual result. Maybe the effect should pin its
         // result if the matrix could over/underflow for any component?
         inout->setToOther(kA_GrColorComponentFlag,
-                          static_cast<uint8_t>(SkScalarPin(outputA, 0, 255)) << GrColor_SHIFT_A);
+                          static_cast<uint8_t>(SkScalarPin(outputA, 0, 255)) << GrColor_SHIFT_A,
+                          InvariantOutput::kWill_ReadInput);
     }
 
     SkColorMatrix fMatrix;