Add an InvariantOutput for the XPF.

include/gpu/effects/GrPorterDuffXferProcessor.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrPorterDuffXferProcessor_DEFINED
 #define GrPorterDuffXferProcessor_DEFINED
 
@@ skipping 115 matching lines @@
     }
 
     GrXferProcessor* createXferProcessor(const GrProcOptInfo& colorPOI,
                                          const GrProcOptInfo& coveragePOI) const SK_OVERRIDE;
 
     bool supportsRGBCoverage(GrColor knownColor, uint32_t knownColorFlags) const SK_OVERRIDE;
 
     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); 
 
     bool onIsEqual(const GrXPFactory& xpfBase) const SK_OVERRIDE {
         const GrPorterDuffXPFactory& xpf = xpfBase.cast<GrPorterDuffXPFactory>();
         return (fSrcCoeff == xpf.fSrcCoeff && fDstCoeff == xpf.fDstCoeff);
     }
 
     GR_DECLARE_XP_FACTORY_TEST;
 
     GrBlendCoeff fSrcCoeff;
     GrBlendCoeff fDstCoeff;
 
     typedef GrXPFactory INHERITED;
 };
 
 #endif