Initial error handling code

include/effects/SkDropShadowImageFilter.h

Index: include/effects/SkDropShadowImageFilter.h
diff --git a/include/effects/SkDropShadowImageFilter.h b/include/effects/SkDropShadowImageFilter.h
index 501df7cf7f6c7816ac40f42eadcae587f1e67606..a78cfb895dbf4675eedda55cbd4873d68e141a4c 100644
--- a/include/effects/SkDropShadowImageFilter.h
+++ b/include/effects/SkDropShadowImageFilter.h
@@ -10,6 +10,8 @@
 #include "SkScalar.h"
 
 class SK_API SkDropShadowImageFilter : public SkImageFilter {
+    typedef SkImageFilter INHERITED;
+
 public:
     SkDropShadowImageFilter(SkScalar dx, SkScalar dy, SkScalar sigma, SkColor, SkImageFilter* input = NULL);
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkDropShadowImageFilter)
@@ -22,5 +24,4 @@ protected:
 private:
     SkScalar fDx, fDy, fSigma;
     SkColor fColor;
-    typedef SkImageFilter INHERITED;
 };