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

tests/ImageTest.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 <functional>
 #include <initializer_list>
 #include <vector>
@@ skipping 333 matching lines @@
     const SkImageInfo dstInfo = SkImageInfo::MakeN32Premul(2, 2);
     const size_t dstRowBytes = 2 * sizeof(SkPMColor);
 
     sk_sp<SkImage> image1(surface->makeImageSnapshot());
     REPORTER_ASSERT(reporter, image1->readPixels(dstInfo, pixels, dstRowBytes, 0, 0));
     for (size_t i = 0; i < SK_ARRAY_COUNT(pixels); ++i) {
         REPORTER_ASSERT(reporter, pixels[i] == green);
     }
 
     SkPaint paint;
-    paint.setXfermodeMode(SkXfermode::kSrc_Mode);
+    paint.setBlendMode(SkBlendMode::kSrc);
     paint.setColor(SK_ColorRED);
 
     surface->getCanvas()->drawRect(SkRect::MakeXYWH(1, 1, 1, 1), paint);
 
     sk_sp<SkImage> image2(surface->makeImageSnapshot());
     REPORTER_ASSERT(reporter, image2->readPixels(dstInfo, pixels, dstRowBytes, 0, 0));
     REPORTER_ASSERT(reporter, pixels[0] == green);
     REPORTER_ASSERT(reporter, pixels[1] == green);
     REPORTER_ASSERT(reporter, pixels[2] == green);
     REPORTER_ASSERT(reporter, pixels[3] == red);
@@ skipping 679 matching lines @@
     SkBitmap bm1;
     bm1.allocPixels(SkImageInfo::MakeN32(256, 256, kUnpremul_SkAlphaType));
     bm0.readPixels(bm1.info(), bm1.getPixels(), bm1.rowBytes(), 0, 0);
 
     SkBitmap bm2;
     bm2.allocPixels(SkImageInfo::MakeN32(256, 256, kPremul_SkAlphaType));
     bm1.readPixels(bm2.info(), bm2.getPixels(), bm2.rowBytes(), 0, 0);
 
     REPORTER_ASSERT(reporter, equal(bm0, bm2));
 }