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

src/core/SkBitmapDevice.cpp

Index: src/core/SkBitmapDevice.cpp
diff --git a/src/core/SkBitmapDevice.cpp b/src/core/SkBitmapDevice.cpp
index 440de68345f4a2c67bd86531939de2ed9feb96d8..26d253cf38dae0ebb80f46a047c9e2eae8b15c50 100644
--- a/src/core/SkBitmapDevice.cpp
+++ b/src/core/SkBitmapDevice.cpp
@@ -446,7 +446,7 @@ bool SkBitmapDevice::onShouldDisableLCD(const SkPaint& paint) const {
         paint.getPathEffect() ||
         paint.isFakeBoldText() ||
         paint.getStyle() != SkPaint::kFill_Style ||
-        !SkXfermode::IsMode(paint.getXfermode(), SkXfermode::kSrcOver_Mode))
+        !paint.isSrcOver())
     {
         return true;
     }