Potentially optimize some GrGLEffects for known input color values

src/effects/SkLightingImageFilter.cpp

 /*
  * Copyright 2012 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLightingImageFilter.h"
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
@@ skipping 1055 matching lines @@
 class GrGLLightingEffect  : public GrGLEffect {
 public:
     GrGLLightingEffect(const GrBackendEffectFactory& factory,
                        const GrDrawEffect& effect);
     virtual ~GrGLLightingEffect();
 
     virtual void emitCode(GrGLShaderBuilder*,
                           const GrDrawEffect&,
                           EffectKey,
                           const char* outputColor,
-                          const char* inputColor,
+                          const GrGLSLExpr4& inputColor,
                           const TransformedCoordsArray&,
                           const TextureSamplerArray&) SK_OVERRIDE;
 
     static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&);
 
     /**
      * Subclasses of GrGLLightingEffect must call INHERITED::setData();
      */
     virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
 
@@ skipping 114 matching lines @@
 }
 
 GrGLLightingEffect::~GrGLLightingEffect() {
     delete fLight;
 }
 
 void GrGLLightingEffect::emitCode(GrGLShaderBuilder* builder,
                                   const GrDrawEffect&,
                                   EffectKey key,
                                   const char* outputColor,
-                                  const char* inputColor,
+                                  const GrGLSLExpr4& inputColor,
                                   const TransformedCoordsArray& coords,
                                   const TextureSamplerArray& samplers) {
     SkString coords2D = builder->ensureFSCoords2D(coords, 0);
 
     fImageIncrementUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
                                               kVec2f_GrSLType,
                                              "ImageIncrement");
     fSurfaceScaleUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
                                            kFloat_GrSLType,
                                            "SurfaceScale");
@@ skipping 337 matching lines @@
 
 #endif
 
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkLightingImageFilter)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkDiffuseLightingImageFilter)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkSpecularLightingImageFilter)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkDistantLight)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkPointLight)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkSpotLight)
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END