Potentially optimize some GrGLEffects for known input color values

src/effects/gradients/SkGradientShaderPriv.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkGradientShaderPriv_DEFINED
 #define SkGradientShaderPriv_DEFINED
 
@@ skipping 353 matching lines @@
     void emitUniforms(GrGLShaderBuilder* builder, EffectKey key);
 
 
     // emit code that gets a fragment's color from an expression for t; Has branches for 3 separate
     // control flows inside -- 2 color gradients, 3 color symmetric gradients (both using
     // native GLSL mix), and 4+ color gradients that use the traditional texture lookup.
     void emitColor(GrGLShaderBuilder* builder,
                    const char* gradientTValue,
                    EffectKey key,
                    const char* outputColor,
-                   const char* inputColor,
+                   const GrGLSLExpr4& inputColor,
                    const TextureSamplerArray& samplers);
 
 private:
     SkScalar fCachedYCoord;
     GrGLUniformManager::UniformHandle fFSYUni;
     GrGLUniformManager::UniformHandle fColorStartUni;
     GrGLUniformManager::UniformHandle fColorMidUni;
     GrGLUniformManager::UniformHandle fColorEndUni;
 
     typedef GrGLEffect INHERITED;
 };
 
 #endif
 
 #endif