Make all blending up to GrOptDrawState be handled by the xp/xp factory.

src/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
 
 #include "GrTypes.h"
 #include "GrXferProcessor.h"
 #include "SkXfermode.h"
 
 class GrBackendFragmentProcessorFactory;
 class GrDrawState;
 class GrGLPorterDuffXferProcessor;
 class GrInvariantOutput;
 
 class GrPorterDuffXferProcessor : public GrXferProcessor {
 public:
-    static GrXferProcessor* Create(GrBlendCoeff srcBlend, GrBlendCoeff dstBlend) {
-        return SkNEW_ARGS(GrPorterDuffXferProcessor, (srcBlend, dstBlend));
+    static GrXferProcessor* Create(GrBlendCoeff srcBlend, GrBlendCoeff dstBlend,
+                                   GrColor constant = 0) {
+        return SkNEW_ARGS(GrPorterDuffXferProcessor, (srcBlend, dstBlend, constant));
     }
 
     virtual ~GrPorterDuffXferProcessor();
 
     virtual const GrBackendFragmentProcessorFactory& getFactory() const SK_OVERRIDE;
 
     typedef GrGLPorterDuffXferProcessor GLProcessor;
     static const char* Name() { return "Porter Duff"; }
 
+    virtual GrXferProcessor::BlendOptFlags getBlendOpts(const GrProcOptInfo& colorPOI,
+                                                        const GrProcOptInfo& coveragePOI,
+                                                        bool isCoverageDrawing,
+                                                        bool colorWriteDisabled,
+                                                        bool doesStencilWrite,
+                                                        GrColor* color,
+                                                        uint8_t* coverage) SK_OVERRIDE;
+
+    virtual void getBlendInfo(GrXferProcessor::BlendInfo* blendInfo) const SK_OVERRIDE {
+        blendInfo->fSrcBlend = fSrcBlend;
+        blendInfo->fDstBlend = fDstBlend;
+        blendInfo->fBlendConstant = fBlendConstant;
+    }
+
 private:
-    GrPorterDuffXferProcessor(GrBlendCoeff srcBlend, GrBlendCoeff dstBlend);
+    GrPorterDuffXferProcessor(GrBlendCoeff srcBlend, GrBlendCoeff dstBlend, GrColor constant);
 
     virtual bool onIsEqual(const GrFragmentProcessor& fpBase) const SK_OVERRIDE {
         const GrPorterDuffXferProcessor& xp = fpBase.cast<GrPorterDuffXferProcessor>();
-        if (fSrcBlend != xp.fSrcBlend || fDstBlend != xp.fDstBlend) {
+        if (fSrcBlend != xp.fSrcBlend ||
+            fDstBlend != xp.fDstBlend ||
+            fBlendConstant != xp.fBlendConstant) {
             return false;
         }
         return true;
     }
 
     virtual void onComputeInvariantOutput(GrInvariantOutput* inout) const SK_OVERRIDE;
 
     GrBlendCoeff fSrcBlend;
     GrBlendCoeff fDstBlend;
-    
+    GrColor      fBlendConstant;
+
     typedef GrXferProcessor INHERITED;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 class GrPorterDuffXPFactory : public GrXPFactory {
 public:
     static GrXPFactory* Create(SkXfermode::Mode mode); 
 
     static GrXPFactory* Create(SkXfermode::Coeff src, SkXfermode::Coeff dst) {
         return SkNEW_ARGS(GrPorterDuffXPFactory, ((GrBlendCoeff)(src), (GrBlendCoeff)(dst)));
     }
 
     static GrXPFactory* Create(GrBlendCoeff src, GrBlendCoeff dst) {
         return SkNEW_ARGS(GrPorterDuffXPFactory, (src, dst));
     }
 
-    const GrXferProcessor* createXferProcessor() const SK_OVERRIDE;
+    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 isCoverageDrawing, bool colorWriteDisabled) const SK_OVERRIDE;
+
+    bool willBlendWithDst(const GrProcOptInfo& colorPOI, const GrProcOptInfo& coveragePOI,
+                          bool isCoverageDrawing, bool colorWriteDisabled) const SK_OVERRIDE;
+
+    bool canTweakAlphaForCoverage(bool isCoverageDrawing) const SK_OVERRIDE;
+
+    bool getOpaqueAndKnownColor(const GrProcOptInfo& colorPOI,
+                                const GrProcOptInfo& coveragePOI,
+                                GrColor* solidColor,
+                                uint32_t* solidColorKnownComponents) const SK_OVERRIDE;
+
 private:
     GrPorterDuffXPFactory(GrBlendCoeff src, GrBlendCoeff dst)
-        : fSrc(src), fDst(dst) {}
+        : fSrcCoeff(src), fDstCoeff(dst) {}
 
-    GrBlendCoeff fSrc;
-    GrBlendCoeff fDst;
+    GrBlendCoeff fSrcCoeff;
+    GrBlendCoeff fDstCoeff;
 
     typedef GrXPFactory INHERITED;
 };
 
 #endif