Potentially optimize some GrGLEffects for known input color values

src/effects/gradients/SkLinearGradient.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLinearGradient.h"
 
 static inline int repeat_bits(int x, const int bits) {
@@ skipping 429 matching lines @@
 
     GrGLLinearGradient(const GrBackendEffectFactory& factory, const GrDrawEffect&)
                        : INHERITED (factory) { }
 
     virtual ~GrGLLinearGradient() { }
 
     virtual void emitCode(GrGLShaderBuilder*,
                           const GrDrawEffect&,
                           EffectKey,
                           const char* outputColor,
-                          const char* inputColor,
+                          const GrGLSLExpr4& inputColor,
                           const TransformedCoordsArray&,
                           const TextureSamplerArray&) SK_OVERRIDE;
 
     static EffectKey GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
         return GenBaseGradientKey(drawEffect);
     }
 
 private:
 
     typedef GrGLGradientEffect INHERITED;
@@ skipping 54 matching lines @@
     SkPaint paint;
     return shader->asNewEffect(context, paint);
 }
 
 /////////////////////////////////////////////////////////////////////
 
 void GrGLLinearGradient::emitCode(GrGLShaderBuilder* builder,
                                   const GrDrawEffect&,
                                   EffectKey key,
                                   const char* outputColor,
-                                  const char* inputColor,
+                                  const GrGLSLExpr4& inputColor,
                                   const TransformedCoordsArray& coords,
                                   const TextureSamplerArray& samplers) {
     this->emitUniforms(builder, key);
     SkString t = builder->ensureFSCoords2D(coords, 0);
     t.append(".x");
     this->emitColor(builder, t.c_str(), key, outputColor, inputColor, samplers);
 }
 
 /////////////////////////////////////////////////////////////////////
 
@@ skipping 21 matching lines @@
     str->append("SkLinearGradient (");
 
     str->appendf("start: (%f, %f)", fStart.fX, fStart.fY);
     str->appendf(" end: (%f, %f) ", fEnd.fX, fEnd.fY);
 
     this->INHERITED::toString(str);
 
     str->append(")");
 }
 #endif