Implement Porter Duff XP with a blend table

include/gpu/GrXferProcessor.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrXferProcessor_DEFINED
 #define GrXferProcessor_DEFINED
 
@@ skipping 33 matching lines @@
     kHSLSaturation_GrBlendEquation,
     kHSLColor_GrBlendEquation,
     kHSLLuminosity_GrBlendEquation,
 
     kFirstAdvancedGrBlendEquation = kScreen_GrBlendEquation,
     kLast_GrBlendEquation = kHSLLuminosity_GrBlendEquation
 };
 
 static const int kGrBlendEquationCnt = kLast_GrBlendEquation + 1;
 
-inline bool GrBlendEquationIsAdvanced(GrBlendEquation equation) {
-    return equation >= kFirstAdvancedGrBlendEquation;
-}
-
 /**
  * Coeffecients for alpha-blending.
  */
 enum GrBlendCoeff {
     kZero_GrBlendCoeff,    //<! 0
     kOne_GrBlendCoeff,     //<! 1
     kSC_GrBlendCoeff,      //<! src color
     kISC_GrBlendCoeff,     //<! one minus src color
     kDC_GrBlendCoeff,      //<! dst color
     kIDC_GrBlendCoeff,     //<! one minus dst color
@@ skipping 109 matching lines @@
         kIgnoreColor_OptFlag              = 0x2,
         /**
          * GrXferProcessor will ignore coverage, thus no need to provide
          */
         kIgnoreCoverage_OptFlag           = 0x4,
         /**
          * Clear color stages and override input color to that returned by getOptimizations
          */
         kOverrideColor_OptFlag            = 0x8,
         /**
-         * Set CoverageDrawing_StateBit
-         */
-        kSetCoverageDrawing_OptFlag       = 0x10,
-        /**
          * Can tweak alpha for coverage. Currently this flag should only be used by a batch
          */
         kCanTweakAlphaForCoverage_OptFlag = 0x20,
     };
 
     GR_DECL_BITFIELD_OPS_FRIENDS(OptFlags);
 
     /**
      * Determines which optimizations (as described by the ptFlags above) can be performed by
      * the draw with this xfer processor. If this function is called, the xfer processor may change
@@ skipping 241 matching lines @@
     enum {
         kIllegalXPFClassID = 0,
     };
     static int32_t gCurrXPFClassID;
 
     typedef GrProgramElement INHERITED;
 };
 
 #endif