Add an InvariantOutput for the XPF.

include/gpu/effects/GrPorterDuffXferProcessor.h

Index: include/gpu/effects/GrPorterDuffXferProcessor.h
diff --git a/include/gpu/effects/GrPorterDuffXferProcessor.h b/include/gpu/effects/GrPorterDuffXferProcessor.h
index bcfd935bf2ab4c3ba33235a17bf7832996c5ceae..fab14c732a852d2a48d8995b13132dbd95441d36 100644
--- a/include/gpu/effects/GrPorterDuffXferProcessor.h
+++ b/include/gpu/effects/GrPorterDuffXferProcessor.h
@@ -133,15 +133,11 @@ public:
     bool canApplyCoverage(const GrProcOptInfo& colorPOI, const GrProcOptInfo& coveragePOI,
                           bool colorWriteDisabled) const SK_OVERRIDE;
 
-    bool willBlendWithDst(const GrProcOptInfo& colorPOI, const GrProcOptInfo& coveragePOI,
-                          bool colorWriteDisabled) const SK_OVERRIDE;
-
     bool canTweakAlphaForCoverage() const SK_OVERRIDE;
 
-    bool getOpaqueAndKnownColor(const GrProcOptInfo& colorPOI,
-                                const GrProcOptInfo& coveragePOI,
-                                GrColor* solidColor,
-                                uint32_t* solidColorKnownComponents) const SK_OVERRIDE;
+    void getInvariantOutput(const GrProcOptInfo& colorPOI, const GrProcOptInfo& coveragePOI,
+                            bool colorWriteDisabled,
+                            GrXPFactory::InvariantOutput*) const SK_OVERRIDE;
 
 private:
     GrPorterDuffXPFactory(GrBlendCoeff src, GrBlendCoeff dst);