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

src/core/SkSpriteBlitter_RGB16.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkSpriteBlitter.h"
 #include "SkBlitRow.h"
@@ skipping 289 matching lines @@
 ///////////////////////////////////////////////////////////////////////////////
 
 SkSpriteBlitter* SkSpriteBlitter::ChooseD16(const SkPixmap& source, const SkPaint& paint,
                                             SkTBlitterAllocator* allocator) {
 
     SkASSERT(allocator != nullptr);
 
     if (paint.getMaskFilter() != nullptr) { // may add cases for this
         return nullptr;
     }
-    if (paint.getXfermode() != nullptr) { // may add cases for this
+    if (!paint.isSrcOver()) { // may add cases for this
         return nullptr;
     }
     if (paint.getColorFilter() != nullptr) { // may add cases for this
         return nullptr;
     }
 
     const SkAlphaType at = source.alphaType();
 
     SkSpriteBlitter* blitter = nullptr;
     unsigned alpha = paint.getAlpha();
@@ skipping 43 matching lines @@
                 } else {
                     blitter = allocator->createT<Sprite_D16_SIndex8A_Blend>(source, alpha);
                 }
             }
             break;
         default:
             break;
     }
     return blitter;
 }