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

gm/plus.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 #include "SkPath.h"
 
@@ skipping 19 matching lines @@
     bottomRight.lineTo(100, 100);
     bottomRight.lineTo(0, 100);
     bottomRight.lineTo(100, 0);
 
     // The left square is drawn simply with SrcOver.  It will show a red seam.
     canvas->drawPath(upperLeft, p);
     canvas->drawPath(bottomRight, p);
 
     // Using Plus on the right should merge the AA of seam together completely covering the red.
     canvas->saveLayer(nullptr, nullptr);
-      p.setXfermodeMode(SkXfermode::kPlus_Mode);
+      p.setBlendMode(SkBlendMode::kPlus);
       canvas->translate(150, 0);
       canvas->drawPath(upperLeft, p);
       canvas->drawPath(bottomRight, p);
     canvas->restore();
 }