factories should return baseclass, allowing the impl to specialize

include/effects/SkOffsetImageFilter.h

Index: include/effects/SkOffsetImageFilter.h
diff --git a/include/effects/SkOffsetImageFilter.h b/include/effects/SkOffsetImageFilter.h
index 30e380d89b03bb00dc68787530da5f817b936109..a56f40972d03c3602ed39f958c3099d46c2d2918 100644
--- a/include/effects/SkOffsetImageFilter.h
+++ b/include/effects/SkOffsetImageFilter.h
@@ -15,8 +15,8 @@ class SK_API SkOffsetImageFilter : public SkImageFilter {
     typedef SkImageFilter INHERITED;
 
 public:
-    static SkOffsetImageFilter* Create(SkScalar dx, SkScalar dy, SkImageFilter* input = NULL,
-                                       const CropRect* cropRect = NULL) {
+    static SkImageFilter* Create(SkScalar dx, SkScalar dy, SkImageFilter* input = NULL,
+                                 const CropRect* cropRect = NULL) {
         if (!SkScalarIsFinite(dx) || !SkScalarIsFinite(dy)) {
             return NULL;
         }
@@ -27,14 +27,14 @@ public:
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkOffsetImageFilter)
 
 protected:
-    SkOffsetImageFilter(SkScalar dx, SkScalar dy, SkImageFilter* input, const CropRect* cropRect);
     void flatten(SkWriteBuffer&) const override;
-
-    virtual bool onFilterImage(Proxy*, const SkBitmap& src, const Context&,
-                               SkBitmap* result, SkIPoint* loc) const override;
+    bool onFilterImage(Proxy*, const SkBitmap& src, const Context&, SkBitmap* result,
+                       SkIPoint* loc) const override;
     bool onFilterBounds(const SkIRect&, const SkMatrix&, SkIRect*) const override;
 
 private:
+    SkOffsetImageFilter(SkScalar dx, SkScalar dy, SkImageFilter* input, const CropRect*);
+
     SkVector fOffset;
 };