Make XPFragmentBuilder only Builder with access to DstCopy.

src/gpu/effects/GrPorterDuffXferProcessor.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "effects/GrPorterDuffXferProcessor.h"
 
 #include "GrBlend.h"
@@ skipping 122 matching lines @@
     GrBlendCoeff fDstBlend;
     GrColor      fBlendConstant;
     PrimaryOutputType fPrimaryOutputType;
     SecondaryOutputType fSecondaryOutputType;
 
     typedef GrXferProcessor INHERITED;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
-bool append_porterduff_term(GrGLFPFragmentBuilder* fsBuilder, GrBlendCoeff coeff,
+bool append_porterduff_term(GrGLXPFragmentBuilder* fsBuilder, GrBlendCoeff coeff,
                             const char* colorName, const char* srcColorName,
                             const char* dstColorName, bool hasPrevious) {
     if (kZero_GrBlendCoeff == coeff) {
         return hasPrevious;
     } else {
         if (hasPrevious) {
             fsBuilder->codeAppend(" + ");
         }
         fsBuilder->codeAppendf("%s", colorName);
         switch (coeff) {
@@ skipping 43 matching lines @@
         b->add32(xp.secondaryOutputType());
         if (xp.willReadDstColor()) {
             b->add32(xp.getSrcBlend());
             b->add32(xp.getDstBlend());
         }
     };
 
 private:
     void onEmitCode(const EmitArgs& args) override {
         const PorterDuffXferProcessor& xp = args.fXP.cast<PorterDuffXferProcessor>();
-        GrGLFPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
+        GrGLXPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
         if (PorterDuffXferProcessor::kCustom_PrimaryOutputType != xp.primaryOutputType()) {
             SkASSERT(!xp.willReadDstColor());
             switch(xp.secondaryOutputType()) {
                 case PorterDuffXferProcessor::kNone_SecondaryOutputType:
                     break;
                 case PorterDuffXferProcessor::kCoverage_SecondaryOutputType:
                     fsBuilder->codeAppendf("%s = %s;", args.fOutputSecondary,
                                            args.fInputCoverage);
                     break;
                 case PorterDuffXferProcessor::kCoverageISA_SecondaryOutputType:
@@ skipping 482 matching lines @@
 GR_DEFINE_XP_FACTORY_TEST(GrPorterDuffXPFactory);
 
 GrXPFactory* GrPorterDuffXPFactory::TestCreate(SkRandom* random,
                                                GrContext*,
                                                const GrDrawTargetCaps&,
                                                GrTexture*[]) {
     SkXfermode::Mode mode = SkXfermode::Mode(random->nextULessThan(SkXfermode::kLastCoeffMode));
     return GrPorterDuffXPFactory::Create(mode);
 }