Revert of Use dst copies in porter duffer XP to correctly render certain blends.

src/gpu/effects/GrCustomXfermode.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "effects/GrCustomXfermode.h"
 #include "effects/GrCustomXfermodePriv.h"
 
@@ skipping 590 matching lines @@
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 GrCustomXPFactory::GrCustomXPFactory(SkXfermode::Mode mode)
     : fMode(mode) {
     this->initClassID<GrCustomXPFactory>();
 }
 
 GrXferProcessor*
-GrCustomXPFactory::onCreateXferProcessor(const GrDrawTargetCaps& caps,
-                                         const GrProcOptInfo& colorPOI,
+GrCustomXPFactory::onCreateXferProcessor(const GrProcOptInfo& colorPOI,
                                          const GrProcOptInfo& coveragePOI,
                                          const GrDeviceCoordTexture* dstCopy) const {
-    return CustomXP::Create(fMode, dstCopy, this->willReadDstColor(caps, colorPOI, coveragePOI));
+    return CustomXP::Create(fMode, dstCopy, this->willReadDstColor(colorPOI, coveragePOI));
 }
 
 
 void GrCustomXPFactory::getInvariantOutput(const GrProcOptInfo& colorPOI,
                                                const GrProcOptInfo& coveragePOI,
                                                GrXPFactory::InvariantOutput* output) const {
     output->fWillBlendWithDst = true;
     output->fBlendedColorFlags = 0;
 }
 
 GR_DEFINE_XP_FACTORY_TEST(GrCustomXPFactory);
 GrXPFactory* GrCustomXPFactory::TestCreate(SkRandom* rand,
                                            GrContext*,
                                            const GrDrawTargetCaps&,
                                            GrTexture*[]) {
     int mode = rand->nextRangeU(SkXfermode::kLastCoeffMode + 1, SkXfermode::kLastSeparableMode);
 
     return SkNEW_ARGS(GrCustomXPFactory, (static_cast<SkXfermode::Mode>(mode)));
 }