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

src/gpu/effects/GrCoverageSetOpXP.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/GrCoverageSetOpXP.h"
 #include "GrColor.h"
@@ skipping 210 matching lines @@
                 return SkRef(&gRevDiffCDXPF);
             }
             break;
         }
         default:
             return NULL;
     }
 }
 
 GrXferProcessor*
-GrCoverageSetOpXPFactory::onCreateXferProcessor(const GrProcOptInfo& colorPOI,
+GrCoverageSetOpXPFactory::onCreateXferProcessor(const GrDrawTargetCaps& caps,
+                                                const GrProcOptInfo& colorPOI,
                                                 const GrProcOptInfo& covPOI,
                                                 const GrDeviceCoordTexture* dstCopy) const {
     return CoverageSetOpXP::Create(fRegionOp, fInvertCoverage);
 }
 
 void GrCoverageSetOpXPFactory::getInvariantOutput(const GrProcOptInfo& colorPOI,
                                                   const GrProcOptInfo& coveragePOI,
                                                   GrXPFactory::InvariantOutput* output) const {
     if (SkRegion::kReplace_Op == fRegionOp) {
         if (coveragePOI.isSolidWhite()) {
@@ skipping 14 matching lines @@
 
 GrXPFactory* GrCoverageSetOpXPFactory::TestCreate(SkRandom* random,
                                                   GrContext*,
                                                   const GrDrawTargetCaps&,
                                                   GrTexture*[]) {
     SkRegion::Op regionOp = SkRegion::Op(random->nextULessThan(SkRegion::kLastOp + 1));
     bool invertCoverage = random->nextBool();
     return GrCoverageSetOpXPFactory::Create(regionOp, invertCoverage);
 }