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

src/core/SkImageFilter.cpp

Index: src/core/SkImageFilter.cpp
diff --git a/src/core/SkImageFilter.cpp b/src/core/SkImageFilter.cpp
index 63095bc65dfbd409ffba74bd55e696a11b293f9e..68183cc444b3bfdf31b936b6aded887166f465ad 100644
--- a/src/core/SkImageFilter.cpp
+++ b/src/core/SkImageFilter.cpp
@@ -281,7 +281,7 @@ sk_sp<SkSpecialImage> SkImageFilter::DrawWithFP(GrContext* context,
                                                 const OutputProperties& outputProperties) {
     GrPaint paint;
     paint.addColorFragmentProcessor(std::move(fp));
-    paint.setPorterDuffXPFactory(SkXfermode::kSrc_Mode);
+    paint.setPorterDuffXPFactory(SkBlendMode::kSrc);
 
     sk_sp<SkColorSpace> colorSpace = sk_ref_sp(outputProperties.colorSpace());
     GrPixelConfig config = GrRenderableConfigForColorSpace(colorSpace.get());