I'm investigating how to make the IPC transfer a bit more secure on the

include/core/SkImageFilter.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImageFilter_DEFINED
 #define SkImageFilter_DEFINED
 
@@ skipping 133 matching lines @@
     // Convenience constructor for 1-input filters.
     explicit SkImageFilter(SkImageFilter* input, const SkIRect* cropRect = NULL);
 
     // Convenience constructor for 2-input filters.
     SkImageFilter(SkImageFilter* input1, SkImageFilter* input2, const SkIRect* cropRect = NULL);
 
     virtual ~SkImageFilter();
 
     explicit SkImageFilter(SkFlattenableReadBuffer& rb);
 
+    virtual bool isA(Type type) const { return (IMAGE_FILTER == type) || INHERITED::isA(type); }
+
     virtual void flatten(SkFlattenableWriteBuffer& wb) const SK_OVERRIDE;
 
     // Default impl returns false
     virtual bool onFilterImage(Proxy*, const SkBitmap& src, const SkMatrix&,
                                SkBitmap* result, SkIPoint* offset);
     // Default impl copies src into dst and returns true
     virtual bool onFilterBounds(const SkIRect&, const SkMatrix&, SkIRect*);
 
     // Sets rect to the intersection of rect and the crop rect. If there
     // is no overlap, returns false and leaves rect unchanged.
     bool applyCropRect(SkIRect* rect) const;
 
 private:
     typedef SkFlattenable INHERITED;
     int fInputCount;
     SkImageFilter** fInputs;
     SkIRect fCropRect;
 };
 
 #endif