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

include/effects/SkRectShaderImageFilter.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkRectShaderImageFilter_DEFINED
 #define SkRectShaderImageFilter_DEFINED
 
 #include "SkImageFilter.h"
 #include "SkRect.h"
 
 class SkShader;
 
 class SK_API SkRectShaderImageFilter : public SkImageFilter {
 public:
     /** Create a new image filter which fills the given rectangle with pixels
      *  produced by the given SkShader. If no rectangle is specified, an output
      *  is produced with the same bounds as the input primitive (even though
      *  the input primitive's pixels are not used for processing).
      *  @param s     Shader to call for processing. Cannot be NULL. Will be
      *               ref'ed by the new image filter.
      *  @param rect  Rectangle of output pixels in which to apply the shader.
      *               If NULL or a given crop edge is not specified, the source
      *               primitive's bounds are used instead.
      */
     SK_ATTR_DEPRECATED("use Create(SkShader*, const CropRect*)")
-    static SkImageFilter* Create(SkShader* s, const SkRect& rect);
-    static SkImageFilter* Create(SkShader* s, const CropRect* rect = NULL);
+    static SkRectShaderImageFilter* Create(SkShader* s, const SkRect& rect);
 
+    static SkRectShaderImageFilter* Create(SkShader* s, const CropRect* rect = NULL);
+    virtual ~SkRectShaderImageFilter();
     bool affectsTransparentBlack() const override;
 
     SK_TO_STRING_OVERRIDE()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkRectShaderImageFilter)
 
 protected:
-    virtual ~SkRectShaderImageFilter();
+    void flatten(SkWriteBuffer&) const override;
 
-    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:
     SkRectShaderImageFilter(SkShader* s, const CropRect* rect);
-
     SkShader*  fShader;
 
     typedef SkImageFilter INHERITED;
 };
 
 #endif