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

This reverts commit c245574ba3d0e2ade6c94b2812de3baa383bf4c4.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2396953002

TBR=

Review-Url: https://codereview.chromium.org/2396953002
diff --git a/src/image/SkImage.cpp b/src/image/SkImage.cpp
index 2870f31..67779ba 100644
--- a/src/image/SkImage.cpp
+++ b/src/image/SkImage.cpp
@@ -259,7 +259,7 @@
     SkCanvas canvas(bm);
 
     SkPaint paint;
-    paint.setXfermodeMode(SkXfermode::kSrc_Mode);
+    paint.setBlendMode(SkBlendMode::kSrc);
     canvas.drawImage(this, -SkIntToScalar(srcX), -SkIntToScalar(srcY), &paint);
 
     return true;