Fix for potential typedef issue

src/effects/SkLumaXfermode.cpp

Index: src/effects/SkLumaXfermode.cpp
diff --git a/src/effects/SkLumaXfermode.cpp b/src/effects/SkLumaXfermode.cpp
index a23e010366ead4e21cc6251ec75c80097994460d..96050f95f2ad14682a32e3f885b692aadbc4654d 100644
--- a/src/effects/SkLumaXfermode.cpp
+++ b/src/effects/SkLumaXfermode.cpp
@@ -18,6 +18,8 @@
 #endif
 
 class SkLumaMaskXfermodeSrcOver : public SkLumaMaskXfermode {
+    typedef SkLumaMaskXfermode INHERITED;
+
 public:
     SkLumaMaskXfermodeSrcOver();
 
@@ -27,7 +29,6 @@ protected:
     SkLumaMaskXfermodeSrcOver(SkFlattenableReadBuffer&);
 
 private:
-    typedef SkLumaMaskXfermode INHERITED;
 
     virtual SkPMColor lumaProc(const SkPMColor a, const SkPMColor b) const;
 };