Revert of Make specialized SrcOver XPFactory (patchset #3 id:40001 of https://codereview.chromium.org/1455273006/ )

Reason for revert:
breaking some builds

Original issue's description:
> Make specialized SrcOver XPFactory
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/a7006d45217d128a94fa53cb4b827cca79bc7049

TBR=bsalomon@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1464933003

3 files changed, 7 insertions, 50 deletions

diff --git a/include/core/SkXfermode.h b/include/core/SkXfermode.h
index 4337d20b61..cb9557f92c 100644
--- a/include/core/SkXfermode.h
+++ b/include/core/SkXfermode.h
@@ -209,13 +209,13 @@ public:
         will install it and own a ref to it. Since the xfermode may or may not assign *xpf, the
         caller should set *xpf to NULL beforehand. XferProcessors cannot use a background texture.
      */
-    virtual bool asXPFactory(const GrXPFactory** xpf) const;
+    virtual bool asXPFactory(GrXPFactory** xpf) const;
 
     /** Returns true if the xfermode can be expressed as an xfer processor factory (xpFactory).
         This helper calls the asXPFactory() virtual. If the xfermode is NULL, it is treated as
         kSrcOver_Mode. It is legal to call this with xpf param NULL to simply test the return value.
      */
-    static bool AsXPFactory(SkXfermode*, const GrXPFactory**);
+    static bool AsXPFactory(SkXfermode*, GrXPFactory**);
 
     SK_TO_STRING_PUREVIRT()
     SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP()
diff --git a/include/gpu/effects/GrCustomXfermode.h b/include/gpu/effects/GrCustomXfermode.h
index 7fe930822a..bcbd5833ca 100644
--- a/include/gpu/effects/GrCustomXfermode.h
+++ b/include/gpu/effects/GrCustomXfermode.h
@@ -18,7 +18,7 @@ class GrTexture;
  */
 namespace GrCustomXfermode {
     bool IsSupportedMode(SkXfermode::Mode mode);
-    const GrXPFactory* CreateXPFactory(SkXfermode::Mode mode);
+    GrXPFactory* CreateXPFactory(SkXfermode::Mode mode);
 };
 
 #endif
diff --git a/include/gpu/effects/GrPorterDuffXferProcessor.h b/include/gpu/effects/GrPorterDuffXferProcessor.h
index 72faeb572c..d297e32908 100644
--- a/include/gpu/effects/GrPorterDuffXferProcessor.h
+++ b/include/gpu/effects/GrPorterDuffXferProcessor.h
@@ -14,9 +14,9 @@
 
 class GrProcOptInfo;
 
-class GrPDXPFactory : public GrXPFactory {
+class GrPorterDuffXPFactory : public GrXPFactory {
 public:
-    static const GrXPFactory* Create(SkXfermode::Mode mode); 
+    static GrXPFactory* Create(SkXfermode::Mode mode); 
 
     bool supportsRGBCoverage(GrColor /*knownColor*/, uint32_t /*knownColorFlags*/) const override {
         return true;
@@ -26,7 +26,7 @@ public:
                                   GrXPFactory::InvariantBlendedColor*) const override;
 
 private:
-    GrPDXPFactory(SkXfermode::Mode);
+    GrPorterDuffXPFactory(SkXfermode::Mode);
 
     GrXferProcessor* onCreateXferProcessor(const GrCaps& caps,
                                            const GrProcOptInfo& colorPOI,
@@ -40,7 +40,7 @@ private:
                           bool hasMixedSamples) const override;
 
     bool onIsEqual(const GrXPFactory& xpfBase) const override {
-        const GrPDXPFactory& xpf = xpfBase.cast<GrPDXPFactory>();
+        const GrPorterDuffXPFactory& xpf = xpfBase.cast<GrPorterDuffXPFactory>();
         return fXfermode == xpf.fXfermode;
     }
 
@@ -53,47 +53,4 @@ private:
     typedef GrXPFactory INHERITED;
 };
 
-class GrSrcOverPDXPFactory : public GrXPFactory {
-public:
-    GrSrcOverPDXPFactory();
-
-    bool supportsRGBCoverage(GrColor /*knownColor*/, uint32_t /*knownColorFlags*/) const override {
-        return true;
-    }
-
-    void getInvariantBlendedColor(const GrProcOptInfo& colorPOI,
-                                  GrXPFactory::InvariantBlendedColor*) const override;
-
-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 {
-        return true;
-    }
-
-    GR_DECLARE_XP_FACTORY_TEST;
-
-    typedef GrXPFactory INHERITED;
-};
-
-namespace GrPorterDuffXPFactory {
-    const GrSrcOverPDXPFactory gSrcOverPDXPFactory;
-
-    inline const GrXPFactory* Create(SkXfermode::Mode mode) {
-        if (SkXfermode::kSrcOver_Mode == mode) {
-            return SkRef(&gSrcOverPDXPFactory);
-        }
-        return GrPDXPFactory::Create(mode);
-    }
-};
-
 #endif