Add mixed samples support to XPs

src/gpu/effects/GrCustomXfermode.cpp

Index: src/gpu/effects/GrCustomXfermode.cpp
diff --git a/src/gpu/effects/GrCustomXfermode.cpp b/src/gpu/effects/GrCustomXfermode.cpp
index 5110cdf72346e07bc67d1e1be523341b9e8f3772..55d4b1a5ff3e82cabbc72d486b72706b122f4c3e 100644
--- a/src/gpu/effects/GrCustomXfermode.cpp
+++ b/src/gpu/effects/GrCustomXfermode.cpp
@@ -529,8 +529,8 @@ public:
         this->initClassID<CustomXP>();
     }
 
-    CustomXP(SkXfermode::Mode mode, const DstTexture* dstTexture)
-        : INHERITED(dstTexture, true),
+    CustomXP(const GrPipelineBuilder& builder, const DstTexture* dstTexture, SkXfermode::Mode mode)
+        : INHERITED(builder, dstTexture, true),
           fMode(mode),
           fHWBlendEquation(static_cast<GrBlendEquation>(-1)) {
         this->initClassID<CustomXP>();
@@ -540,8 +540,6 @@ public:
 
     GrGLXferProcessor* createGLInstance() const override;
 
-    bool hasSecondaryOutput() const override { return false; }
-
     SkXfermode::Mode mode() const { return fMode; }
     bool hasHWBlendEquation() const { return -1 != static_cast<int>(fHWBlendEquation); }
 
@@ -793,6 +791,7 @@ GrCustomXPFactory::GrCustomXPFactory(SkXfermode::Mode mode)
 
 GrXferProcessor*
 GrCustomXPFactory::onCreateXferProcessor(const GrCaps& caps,
+                                         const GrPipelineBuilder& builder,
                                          const GrProcOptInfo& colorPOI,
                                          const GrProcOptInfo& coveragePOI,
                                          const DstTexture* dstTexture) const {
@@ -800,10 +799,11 @@ GrCustomXPFactory::onCreateXferProcessor(const GrCaps& caps,
         SkASSERT(!dstTexture || !dstTexture->texture());
         return SkNEW_ARGS(CustomXP, (fMode, fHWBlendEquation));
     }
-    return SkNEW_ARGS(CustomXP, (fMode, dstTexture));
+    return SkNEW_ARGS(CustomXP, (builder, dstTexture, fMode));
 }
 
 bool GrCustomXPFactory::willReadDstColor(const GrCaps& caps,
+                                         const GrPipelineBuilder&,
                                          const GrProcOptInfo& colorPOI,
                                          const GrProcOptInfo& coveragePOI) const {
     return !can_use_hw_blend_equation(fHWBlendEquation, coveragePOI, caps);