Remove SK_SUPPORT_LEGACY_PUBLICEFFECTCONSTRUCTORS flag.

include/core/SkXfermode.h

Index: include/core/SkXfermode.h
diff --git a/include/core/SkXfermode.h b/include/core/SkXfermode.h
index 88f3f620d22c5bb81ace09137d5ead43846cfb67..13749fd51bce74423ad417d3ec8b26a12267ef3f 100644
--- a/include/core/SkXfermode.h
+++ b/include/core/SkXfermode.h
@@ -216,7 +216,8 @@ public:
     SK_DEFINE_FLATTENABLE_TYPE(SkXfermode)
 
 protected:
-    SkXfermode(SkReadBuffer& rb) : SkFlattenable(rb) {}
+    SkXfermode() {}
+    explicit SkXfermode(SkReadBuffer& rb) : SkFlattenable(rb) {}
 
     /** The default implementation of xfer32/xfer16/xferA8 in turn call this
         method, 1 color at a time (upscaled to a SkPMColor). The default
@@ -228,11 +229,6 @@ protected:
     */
     virtual SkPMColor xferColor(SkPMColor src, SkPMColor dst) const;
 
-#ifdef SK_SUPPORT_LEGACY_PUBLICEFFECTCONSTRUCTORS
-public:
-#endif
-    SkXfermode() {}
-
 private:
     enum {
         kModeCount = kLastMode + 1