Revert of Revert "Serialization of SkPictureImageFilter"

include/effects/SkPictureImageFilter.h

Index: include/effects/SkPictureImageFilter.h
diff --git a/include/effects/SkPictureImageFilter.h b/include/effects/SkPictureImageFilter.h
index eeaf1d2e460a06d33222acbe8f8ef36d54d8779d..a10d23eebb2454264552d4c27602563aab5072f1 100644
--- a/include/effects/SkPictureImageFilter.h
+++ b/include/effects/SkPictureImageFilter.h
@@ -28,7 +28,13 @@
 
 protected:
     virtual ~SkPictureImageFilter();
-    explicit SkPictureImageFilter(SkReadBuffer& buffer);
+    /*  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 SkMatrix&,
                                SkBitmap* result, SkIPoint* offset) const SK_OVERRIDE;