Use SkXfermode as public facing enum for GrPorterDuffXP

src/gpu/GrPipelineBuilder.h

Index: src/gpu/GrPipelineBuilder.h
diff --git a/src/gpu/GrPipelineBuilder.h b/src/gpu/GrPipelineBuilder.h
index 72f8e28c579891438ea9ceedd40f06d14ea57e53..ad509e14f8a57cb1e3203661daeec2b80b5024c6 100644
--- a/src/gpu/GrPipelineBuilder.h
+++ b/src/gpu/GrPipelineBuilder.h
@@ -114,14 +114,6 @@ public:
         return xpFactory;
     }
 
-    void setPorterDuffXPFactory(SkXfermode::Mode mode) {
-        fXPFactory.reset(GrPorterDuffXPFactory::Create(mode));
-    }
-
-    void setPorterDuffXPFactory(GrBlendCoeff src, GrBlendCoeff dst) {
-        fXPFactory.reset(GrPorterDuffXPFactory::Create(src, dst));
-    }
-
     void setCoverageSetOpXPFactory(SkRegion::Op regionOp, bool invertCoverage = false) {
         fXPFactory.reset(GrCoverageSetOpXPFactory::Create(regionOp, invertCoverage));
     }