remove unused code around SK_SUPPORT_LEGACY_XFERMODE_PARAM

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4384

Change-Id: I5121acd027d935ade169ff65941f29f654a47bd0
Reviewed-on: https://skia-review.googlesource.com/4384
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/include/effects/SkLayerDrawLooper.h b/include/effects/SkLayerDrawLooper.h
index fd693f7..2c0b68d 100644
--- a/include/effects/SkLayerDrawLooper.h
+++ b/include/effects/SkLayerDrawLooper.h
@@ -56,10 +56,10 @@
      *      kDst_Mode: to just keep the draw's color, ignoring the layer's
      */
     struct SK_API LayerInfo {
-        BitFlags            fPaintBits;
-        SK_XFERMODE_MODE_PARAM fColorMode;
-        SkVector            fOffset;
-        bool                fPostTranslate; //!< applies to fOffset
+        BitFlags    fPaintBits;
+        SkBlendMode fColorMode;
+        SkVector    fOffset;
+        bool        fPostTranslate; //!< applies to fOffset
 
         /**
          *  Initial the LayerInfo. Defaults to settings that will draw the