Don't create a GXPFactory when blend is SrcOver

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
 
 #include "GrTypes.h"
 #include "GrXferProcessor.h"
 #include "SkXfermode.h"
 
 class GrProcOptInfo;
 
 class GrPorterDuffXPFactory : public GrXPFactory {
 public:
-    static GrXPFactory* Create(SkXfermode::Mode mode); 
-
-    bool supportsRGBCoverage(GrColor /*knownColor*/, uint32_t /*knownColorFlags*/) const override {
-        return true;
-    }
-
     void getInvariantBlendedColor(const GrProcOptInfo& colorPOI,
                                   GrXPFactory::InvariantBlendedColor*) const override;
 
 private:
     GrPorterDuffXPFactory(SkXfermode::Mode);
 
+    static GrXPFactory* InternalCreate(SkXfermode::Mode mode); 
+
+public:
+    static inline GrXPFactory* Create(SkXfermode::Mode mode) {
+        if (SkXfermode::kSrc_Mode == mode) {

[egdaniel, 2015/11/23 20:10:15]

Since Src is our second most common blend mode, and we explicitly creating a
SrcMode XP in multiple spots throughout the code, I figured we could do a little
to try and speed it up.

This is totally optional and happy to remove it if we don't want it.

[bsalomon, 2015/11/23 20:19:51]

second most common in real content? My instinct is to remove it unless src is
really > ~10% of draws since this whole thing a very micro optimization.

[egdaniel, 2015/11/23 20:49:04]

removed

+            static GrPorterDuffXPFactory gSrcPDXPF(SkXfermode::kSrc_Mode);
+            return SkRef(&gSrcPDXPF);
+        }
+        return InternalCreate(mode);
+    }
+    
+private:
     GrXferProcessor* onCreateXferProcessor(const GrCaps& caps,
                                            const GrProcOptInfo& colorPOI,
                                            const GrProcOptInfo& coveragePOI,
                                            bool hasMixedSamples,
                                            const DstTexture*) const override;
 
     bool willReadDstColor(const GrCaps& caps,
                           const GrProcOptInfo& colorPOI,
                           const GrProcOptInfo& coveragePOI,
                           bool hasMixedSamples) const override;
 
     bool onIsEqual(const GrXPFactory& xpfBase) const override {
         const GrPorterDuffXPFactory& xpf = xpfBase.cast<GrPorterDuffXPFactory>();
         return fXfermode == xpf.fXfermode;
     }
 
     GR_DECLARE_XP_FACTORY_TEST;
     static void TestGetXPOutputTypes(const GrXferProcessor*, int* outPrimary, int* outSecondary);
 
     SkXfermode::Mode fXfermode;
 
     friend class GrPorterDuffTest; // for TestGetXPOutputTypes()
     typedef GrXPFactory INHERITED;
 };
 
+GrXferProcessor* GrCreateSrcOverXferProcessor(const GrCaps& caps,

[bsalomon, 2015/11/23 20:19:51]

Should this be GrPorterDuffXPFactory::CreateSrcOverXferProcessor?

[egdaniel, 2015/11/23 20:49:04]

Done.

+                                              const GrProcOptInfo& colorPOI,
+                                              const GrProcOptInfo& coveragePOI,
+                                              bool hasMixedSamples,
+                                              const GrXferProcessor::DstTexture*);
+
+inline void GrSrcOverInvariantBlendedColor(GrColor inputColor,
+                                           GrColorComponentFlags validColorFlags,
+                                           bool isOpaque,
+                                           GrXPFactory::InvariantBlendedColor* blendedColor) {
+    if (!isOpaque) {
+        blendedColor->fWillBlendWithDst = true;
+        blendedColor->fKnownColorFlags = kNone_GrColorComponentFlags;
+        return;
+    }
+    blendedColor->fWillBlendWithDst = false;
+
+    blendedColor->fKnownColor = inputColor;
+    blendedColor->fKnownColorFlags = validColorFlags;
+}
+
+bool GrSrcOverWillNeedDstTexture(const GrCaps& caps,
+                                 const GrProcOptInfo& colorPOI,
+                                 const GrProcOptInfo& coveragePOI,
+                                 bool hasMixedSamples);
+
 #endif