Create helper functions to use in computeInvariantOutput calls

src/gpu/effects/GrOvalEffect.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 "GrOvalEffect.h"
 
@@ skipping 39 matching lines @@
     typedef GrFragmentProcessor INHERITED;
 };
 
 GrFragmentProcessor* CircleEffect::Create(GrPrimitiveEdgeType edgeType, const SkPoint& center,
                                           SkScalar radius) {
     SkASSERT(radius >= 0);
     return SkNEW_ARGS(CircleEffect, (edgeType, center, radius));
 }
 
 void CircleEffect::onComputeInvariantOutput(InvariantOutput* inout) const {
-    inout->fValidFlags = 0;
-    inout->fIsSingleComponent = false;
+    inout->mulByUnknownAlpha();
 }
 
 const GrBackendFragmentProcessorFactory& CircleEffect::getFactory() const {
     return GrTBackendFragmentProcessorFactory<CircleEffect>::getInstance();
 }
 
 CircleEffect::CircleEffect(GrPrimitiveEdgeType edgeType, const SkPoint& c, SkScalar r)
     : fCenter(c)
     , fRadius(r)
     , fEdgeType(edgeType) {
@@ skipping 153 matching lines @@
 
 GrFragmentProcessor* EllipseEffect::Create(GrPrimitiveEdgeType edgeType,
                                            const SkPoint& center,
                                            SkScalar rx,
                                            SkScalar ry) {
     SkASSERT(rx >= 0 && ry >= 0);
     return SkNEW_ARGS(EllipseEffect, (edgeType, center, rx, ry));
 }
 
 void EllipseEffect::onComputeInvariantOutput(InvariantOutput* inout) const {
-    inout->fValidFlags = 0;
-    inout->fIsSingleComponent = false;
+    inout->mulByUnknownAlpha();
 }
 
 const GrBackendFragmentProcessorFactory& EllipseEffect::getFactory() const {
     return GrTBackendFragmentProcessorFactory<EllipseEffect>::getInstance();
 }
 
 EllipseEffect::EllipseEffect(GrPrimitiveEdgeType edgeType, const SkPoint& c, SkScalar rx, SkScalar ry)
     : fCenter(c)
     , fRadii(SkVector::Make(rx, ry))
     , fEdgeType(edgeType) {
@@ skipping 136 matching lines @@
         w /= 2;
         return CircleEffect::Create(edgeType, SkPoint::Make(oval.fLeft + w, oval.fTop + w), w);
     } else {
         w /= 2;
         h /= 2;
         return EllipseEffect::Create(edgeType, SkPoint::Make(oval.fLeft + w, oval.fTop + h), w, h);
     }
 
     return NULL;
 }