Don't create a GXPFactory when blend is SrcOver

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 d297e3290854c01e1d963df5c5f9f1b68fc4ac19..ea53dce78b0f00b4b25d83fc5a8d39e806f7f64d 100644
--- a/include/gpu/effects/GrPorterDuffXferProcessor.h
+++ b/include/gpu/effects/GrPorterDuffXferProcessor.h
@@ -16,18 +16,24 @@ 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,
@@ -53,4 +59,30 @@ private:
     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