don't memtion SkXfermode in public

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=5070

Change-Id: Ia9527bfd0f13146669df5e71098af903e14bae3a
Reviewed-on: https://skia-review.googlesource.com/5070
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/include/core/SkPaint.h b/include/core/SkPaint.h
index ace98fa..de3b479 100644
--- a/include/core/SkPaint.h
+++ b/include/core/SkPaint.h
@@ -12,7 +12,7 @@
 #include "SkColor.h"
 #include "SkFilterQuality.h"
 #include "SkMatrix.h"
-#include "SkXfermode.h"
+#include "SkRefCnt.h"
 
 class SkAutoDescriptor;
 class SkAutoGlyphCache;
@@ -1056,7 +1056,7 @@
     SkColor         fColor;
     SkScalar        fWidth;
     SkScalar        fMiterLimit;
-    uint32_t        fBlendMode; // just need 5-6 bits for SkXfermode::Mode
+    uint32_t        fBlendMode; // just need 5-6 bits
     union {
         struct {
             // all of these bitfields should add up to 32