added support for PLS path rendering

src/gpu/effects/GrCoverageSetOpXP.cpp

Index: src/gpu/effects/GrCoverageSetOpXP.cpp
diff --git a/src/gpu/effects/GrCoverageSetOpXP.cpp b/src/gpu/effects/GrCoverageSetOpXP.cpp
index 7761a6445ac14f91c2fda6984a387cc916ec2a27..8c98c6c84324a01c64a6ddd106352c60168d1c99 100644
--- a/src/gpu/effects/GrCoverageSetOpXP.cpp
+++ b/src/gpu/effects/GrCoverageSetOpXP.cpp
@@ -9,6 +9,7 @@
 #include "effects/GrCoverageSetOpXP.h"
 #include "GrCaps.h"
 #include "GrColor.h"
+#include "GrPipeline.h"
 #include "GrProcessor.h"
 #include "GrProcOptInfo.h"
 #include "glsl/GrGLSLBlend.h"
@@ -151,7 +152,6 @@ class ShaderCSOXferProcessor : public GrXferProcessor {
 public:
     ShaderCSOXferProcessor(const DstTexture* dstTexture,
                            bool hasMixedSamples,
-                           SkXfermode::Mode xfermode,
                            SkRegion::Op regionOp,
                            bool invertCoverage)
         : INHERITED(dstTexture, true, hasMixedSamples)
@@ -323,6 +323,9 @@ GrCoverageSetOpXPFactory::onCreateXferProcessor(const GrCaps& caps,
         return nullptr;
     }
 
+    if (optimizations.fOverrides.fUsePLSDstRead) {
+        return new ShaderCSOXferProcessor(dst, hasMixedSamples, fRegionOp, fInvertCoverage);
+    }
     return CoverageSetOpXP::Create(fRegionOp, fInvertCoverage);
 }