Potentially optimize some GrGLEffects for known input color values

src/gpu/effects/GrBicubicEffect.cpp

 #include "GrBicubicEffect.h"
 
 #define DS(x) SkDoubleToScalar(x)
 
 const SkScalar GrBicubicEffect::gMitchellCoefficients[16] = {
     DS( 1.0 / 18.0), DS(-9.0 / 18.0), DS( 15.0 / 18.0), DS( -7.0 / 18.0),
     DS(16.0 / 18.0), DS( 0.0 / 18.0), DS(-36.0 / 18.0), DS( 21.0 / 18.0),
     DS( 1.0 / 18.0), DS( 9.0 / 18.0), DS( 27.0 / 18.0), DS(-21.0 / 18.0),
     DS( 0.0 / 18.0), DS( 0.0 / 18.0), DS( -6.0 / 18.0), DS(  7.0 / 18.0),
 };
 
 
 class GrGLBicubicEffect : public GrGLEffect {
 public:
     GrGLBicubicEffect(const GrBackendEffectFactory& factory,
                       const GrDrawEffect&);
     virtual void emitCode(GrGLShaderBuilder*,
                           const GrDrawEffect&,
                           EffectKey,
                           const char* outputColor,
-                          const char* inputColor,
+                          const GrGLSLExpr4& inputColor,
                           const TransformedCoordsArray&,
                           const TextureSamplerArray&) SK_OVERRIDE;
 
     virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
 
 private:
     typedef GrGLUniformManager::UniformHandle        UniformHandle;
 
     UniformHandle       fCoefficientsUni;
     UniformHandle       fImageIncrementUni;
 
     typedef GrGLEffect INHERITED;
 };
 
 GrGLBicubicEffect::GrGLBicubicEffect(const GrBackendEffectFactory& factory, const GrDrawEffect&)
     : INHERITED(factory) {
 }
 
 void GrGLBicubicEffect::emitCode(GrGLShaderBuilder* builder,
                                  const GrDrawEffect&,
                                  EffectKey key,
                                  const char* outputColor,
-                                 const char* inputColor,
+                                 const GrGLSLExpr4& inputColor,
                                  const TransformedCoordsArray& coords,
                                  const TextureSamplerArray& samplers) {
     sk_ignore_unused_variable(inputColor);
 
     SkString coords2D = builder->ensureFSCoords2D(coords, 0);
     fCoefficientsUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
                                            kMat44f_GrSLType, "Coefficients");
     fImageIncrementUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
                                              kVec2f_GrSLType, "ImageIncrement");
 
@@ skipping 95 matching lines @@
                                          const GrDrawTargetCaps&,
                                          GrTexture* textures[]) {
     int texIdx = random->nextBool() ? GrEffectUnitTest::kSkiaPMTextureIdx :
                                       GrEffectUnitTest::kAlphaTextureIdx;
     SkScalar coefficients[16];
     for (int i = 0; i < 16; i++) {
         coefficients[i] = random->nextSScalar1();
     }
     return GrBicubicEffect::Create(textures[texIdx], coefficients);
 }