Create helper functions to use in computeInvariantOutput calls

src/gpu/effects/GrSingleTextureEffect.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrSingleTextureEffect_DEFINED
 #define GrSingleTextureEffect_DEFINED
 
@@ skipping 31 matching lines @@
                fCoordTransform.getMatrix().cheapEqualTo(other.fCoordTransform.getMatrix()) &&
                fCoordTransform.sourceCoords() == other.fCoordTransform.sourceCoords();
     }
 
     /**
      * Can be used as a helper to implement subclass onComputeInvariantOutput(). It assumes that
      * the subclass output color will be a modulation of the input color with a value read from the
      * texture.
      */
     void updateInvariantOutputForModulation(InvariantOutput* inout) const {
-        if (inout->isOpaque() && GrPixelConfigIsOpaque(this->texture(0)->config())) {
-            inout->fValidFlags = kA_GrColorComponentFlag;
+        if (GrPixelConfigIsOpaque(this->texture(0)->config())) {
+            inout->mulByUnknownOpaqueColor();
         } else {
-            inout->fValidFlags = 0;
+            inout->mulByUnknownColor();
         }
     }
 
 private:
     GrCoordTransform fCoordTransform;
     GrTextureAccess  fTextureAccess;
 
     typedef GrFragmentProcessor INHERITED;
 };
 
 #endif