Create helper functions to use in computeInvariantOutput calls

src/gpu/effects/GrConvexPolyEffect.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gl/builders/GrGLProgramBuilder.h"
 #include "GrConvexPolyEffect.h"
 
@@ skipping 28 matching lines @@
     }
 
     virtual bool onIsEqual(const GrProcessor& other) const SK_OVERRIDE {
         const AARectEffect& aare = other.cast<AARectEffect>();
         return fRect == aare.fRect;
     }
 
     virtual void onComputeInvariantOutput(InvariantOutput* inout) const SK_OVERRIDE {
         if (fRect.isEmpty()) {
             // An empty rect will have no coverage anywhere.
-            inout->fColor = 0x00000000;
-            inout->fValidFlags = kRGBA_GrColorComponentFlags;
+            inout->setToTransparentBlack();
         } else {
-            inout->fValidFlags = 0;
+            inout->mulByUnknownAlpha();
         }
-        inout->fIsSingleComponent = false;
     }
 
     SkRect              fRect;
     GrPrimitiveEdgeType fEdgeType;
 
     typedef GrFragmentProcessor INHERITED;
 
     GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
 
 };
@@ skipping 257 matching lines @@
 GrFragmentProcessor* GrConvexPolyEffect::Create(GrPrimitiveEdgeType edgeType, const SkRect& rect) {
     if (kHairlineAA_GrProcessorEdgeType == edgeType){
         return NULL;
     }
     return AARectEffect::Create(edgeType, rect);
 }
 
 GrConvexPolyEffect::~GrConvexPolyEffect() {}
 
 void GrConvexPolyEffect::onComputeInvariantOutput(InvariantOutput* inout) const {
-    inout->fValidFlags = 0;
-    inout->fIsSingleComponent = false;
+    inout->mulByUnknownAlpha();
 }
 
 const GrBackendFragmentProcessorFactory& GrConvexPolyEffect::getFactory() const {
     return GrTBackendFragmentProcessorFactory<GrConvexPolyEffect>::getInstance();
 }
 
 GrConvexPolyEffect::GrConvexPolyEffect(GrPrimitiveEdgeType edgeType, int n, const SkScalar edges[])
     : fEdgeType(edgeType)
     , fEdgeCount(n) {
     // Factory function should have already ensured this.
@@ skipping 29 matching lines @@
     }
 
     GrFragmentProcessor* fp;
     do {
         GrPrimitiveEdgeType edgeType = static_cast<GrPrimitiveEdgeType>(
                                         random->nextULessThan(kGrProcessorEdgeTypeCnt));
         fp = GrConvexPolyEffect::Create(edgeType, count, edges);
     } while (NULL == fp);
     return fp;
 }