Create xfer processor backend.

src/gpu/GrProgramDesc.h

Index: src/gpu/GrProgramDesc.h
diff --git a/src/gpu/GrProgramDesc.h b/src/gpu/GrProgramDesc.h
index a20b99f74948c91377c7127ef12a17ff683b019b..3d53842e43ae2cab3a9ddaee0062c353c25593db 100644
--- a/src/gpu/GrProgramDesc.h
+++ b/src/gpu/GrProgramDesc.h
@@ -55,36 +55,6 @@ public:
     }
 
 
-    ///////////////////////////////////////////////////////////////////////////
-    /// @name Stage Output Types
-    ////
-
-    enum PrimaryOutputType {
-        // Modulate color and coverage, write result as the color output.
-        kModulate_PrimaryOutputType,
-        // Combines the coverage, dst, and color as coverage * color + (1 - coverage) * dst. This
-        // can only be set if fDstReadKey is non-zero.
-        kCombineWithDst_PrimaryOutputType,
-
-        kPrimaryOutputTypeCnt,
-    };
-
-    enum SecondaryOutputType {
-        // There is no secondary output
-        kNone_SecondaryOutputType,
-        // Writes coverage as the secondary output. Only set if dual source blending is supported
-        // and primary output is kModulate.
-        kCoverage_SecondaryOutputType,
-        // Writes coverage * (1 - colorA) as the secondary output. Only set if dual source blending
-        // is supported and primary output is kModulate.
-        kCoverageISA_SecondaryOutputType,
-        // Writes coverage * (1 - colorRGBA) as the secondary output. Only set if dual source
-        // blending is supported and primary output is kModulate.
-        kCoverageISC_SecondaryOutputType,
-
-        kSecondaryOutputTypeCnt,
-    };
-
     // Specifies where the initial color comes from before the stages are applied.
     enum ColorInput {
         kAllOnes_ColorInput,
@@ -105,9 +75,6 @@ public:
         ColorInput                  fColorInput : 8;
         ColorInput                  fCoverageInput : 8;
 
-        PrimaryOutputType           fPrimaryOutputType : 8;
-        SecondaryOutputType         fSecondaryOutputType : 8;
-
         SkBool8                     fHasGeometryProcessor;
         int8_t                      fColorEffectCnt;
         int8_t                      fCoverageEffectCnt;
@@ -140,10 +107,7 @@ public:
                    fInputCoverageIsUsed == that.fInputCoverageIsUsed &&
                    fReadsDst == that.fReadsDst &&
                    fReadsFragPosition == that.fReadsFragPosition &&
-                   fRequiresLocalCoordAttrib == that.fRequiresLocalCoordAttrib &&
-                   fPrimaryOutputType == that.fPrimaryOutputType &&
-                   fSecondaryOutputType == that.fSecondaryOutputType;
-
+                   fRequiresLocalCoordAttrib == that.fRequiresLocalCoordAttrib;
         }
         bool operator!=(const DescInfo& that) const { return !(*this == that); };
         // TODO when GPs control uniform / attribute handling of color / coverage, then we can
@@ -162,9 +126,6 @@ public:
         bool            fReadsFragPosition;
         bool            fRequiresLocalCoordAttrib;
 
-        // Fragment shader color outputs
-        GrProgramDesc::PrimaryOutputType  fPrimaryOutputType : 8;
-        GrProgramDesc::SecondaryOutputType  fSecondaryOutputType : 8;
     };
 
 private: