Revert of factories should return baseclass, allowing the impl to specialize

include/effects/SkTestImageFilters.h

Index: include/effects/SkTestImageFilters.h
diff --git a/include/effects/SkTestImageFilters.h b/include/effects/SkTestImageFilters.h
index 06a3ff31a14e17107232f17933eb9d52779da6b3..4fa0c430f34fa5cdcbc88ca4fea3d8d1969a5c59 100644
--- a/include/effects/SkTestImageFilters.h
+++ b/include/effects/SkTestImageFilters.h
@@ -14,7 +14,7 @@
 // Fun mode that scales down (only) and then scales back up to look pixelated
 class SK_API SkDownSampleImageFilter : public SkImageFilter {
 public:
-    static SkImageFilter* Create(SkScalar scale, SkImageFilter* input = NULL) {
+    static SkDownSampleImageFilter* Create(SkScalar scale, SkImageFilter* input = NULL) {
         if (!SkScalarIsFinite(scale)) {
             return NULL;
         }
@@ -29,14 +29,14 @@
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkDownSampleImageFilter)
 
 protected:
+    SkDownSampleImageFilter(SkScalar scale, SkImageFilter* input)
+      : INHERITED(1, &input), fScale(scale) {}
     void flatten(SkWriteBuffer&) const override;
-    bool onFilterImage(Proxy*, const SkBitmap& src, const Context&, SkBitmap* result,
-                       SkIPoint* loc) const override;
+
+    virtual bool onFilterImage(Proxy*, const SkBitmap& src, const Context&,
+                               SkBitmap* result, SkIPoint* loc) const override;
 
 private:
-    SkDownSampleImageFilter(SkScalar scale, SkImageFilter* input)
-        : INHERITED(1, &input), fScale(scale) {}
-
     SkScalar fScale;
 
     typedef SkImageFilter INHERITED;