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

src/core/SkBitmapDevice.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmapDevice.h"
 #include "SkConfig8888.h"
 #include "SkDraw.h"
@@ skipping 428 matching lines @@
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 bool SkBitmapDevice::onShouldDisableLCD(const SkPaint& paint) const {
     if (kN32_SkColorType != fBitmap.colorType() ||
         paint.getRasterizer() ||
         paint.getPathEffect() ||
         paint.isFakeBoldText() ||
         paint.getStyle() != SkPaint::kFill_Style ||
-        !SkXfermode::IsMode(paint.getXfermode(), SkXfermode::kSrcOver_Mode))
+        !paint.isSrcOver())
     {
         return true;
     }
     return false;
 }