Implement SkPictureImageFilter bounds computation.

include/effects/SkPictureImageFilter.h

 /*
  * Copyright 2013 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkPictureImageFilter_DEFINED
 #define SkPictureImageFilter_DEFINED
 
@@ skipping 26 matching lines @@
     /*  Constructs an SkPictureImageFilter object from an SkReadBuffer.
      *  Note: If the SkPictureImageFilter object construction requires bitmap
      *  decoding, the decoder must be set on the SkReadBuffer parameter by calling
      *  SkReadBuffer::setBitmapDecoder() before calling this constructor.
      *  @param SkReadBuffer Serialized picture data.
      */
     explicit SkPictureImageFilter(SkReadBuffer&);
     virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
     virtual bool onFilterImage(Proxy*, const SkBitmap& src, const Context&,
                                SkBitmap* result, SkIPoint* offset) const SK_OVERRIDE;
+    virtual bool onFilterBounds(const SkIRect& src, const SkMatrix&,
+                                SkIRect* dst) const SK_OVERRIDE;
 
 private:
     SkPicture* fPicture;
     SkRect     fCropRect;
     typedef SkImageFilter INHERITED;
 };
 
 #endif