Implement color filter as GrGLEffect

src/gpu/gl/GrGLProgramDesc.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGLProgramDesc_DEFINED
 #define GrGLProgramDesc_DEFINED
 
@@ skipping 142 matching lines @@
 
         // should the FS discard if the coverage is zero (to avoid stencil manipulation)
         SkBool8                     fDiscardIfZeroCoverage;
 
         ColorInput                  fColorInput : 8;
         ColorInput                  fCoverageInput : 8;
         CoverageOutput              fCoverageOutput : 8;
 
         SkBool8                     fHasVertexCode;
         SkBool8                     fEmitsPointSize;
-        SkXfermode::Mode            fColorFilterXfermode : 8;
 
         // To enable experimental geometry shader code (not for use in
         // production)
 #if GR_GL_EXPERIMENTAL_GS
         SkBool8                     fExperimentalGS;
 #endif
 
         int8_t                      fPositionAttributeIndex;
         int8_t                      fLocalCoordAttributeIndex;
         int8_t                      fColorAttributeIndex;
@@ skipping 45 matching lines @@
 
     // GrGLProgram and GrGLShaderBuilder read the private fields to generate code. TODO: Move all
     // code generation to GrGLShaderBuilder (and maybe add getters rather than friending).
     friend class GrGLProgram;
     friend class GrGLShaderBuilder;
     friend class GrGLFullShaderBuilder;
     friend class GrGLFragmentOnlyShaderBuilder;
 };
 
 #endif