Revert[8] "replace SkXfermode obj with SkBlendMode enum in paints"

src/core/SkSpriteBlitter4f.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkSpriteBlitter.h"
 #include "SkSpanProcs.h"
 #include "SkTemplates.h"
 #include "SkXfermode.h"
 
 class Sprite_4f : public SkSpriteBlitter {
 public:
     Sprite_4f(const SkPixmap& src, const SkPaint& paint) : INHERITED(src) {
-        fXfer = paint.getXfermode();
+        fXfer = SkXfermode::Peek(paint.getBlendMode());
         fLoader = SkLoadSpanProc_Choose(src.info());
         fFilter = SkFilterSpanProc_Choose(paint);
         fBuffer.reset(src.width());
     }
 
 protected:
     SkXfermode*             fXfer;
     SkLoadSpanProc          fLoader;
     SkFilterSpanProc        fFilter;
     SkAutoTMalloc<SkPM4f>   fBuffer;
@@ skipping 93 matching lines @@
     }
 
     switch (source.colorType()) {
         case kN32_SkColorType:
         case kRGBA_F16_SkColorType:
             return allocator->createT<Sprite_sRGB>(source, paint);
         default:
             return nullptr;
     }
 }