Revert of Revert "Serialization of SkPictureImageFilter"

include/core/SkPicture.h

Index: include/core/SkPicture.h
diff --git a/include/core/SkPicture.h b/include/core/SkPicture.h
index 82d6835dbd9e15906f53d3e550439d9b20d95263..a717153dbed9aef0c090e49610a73184d92a6c9f 100644
--- a/include/core/SkPicture.h
+++ b/include/core/SkPicture.h
@@ -67,6 +67,16 @@
      */
     static SkPicture* CreateFromStream(SkStream*,
                                        InstallPixelRefProc proc = &SkImageDecoder::DecodeMemory);
+
+    /**
+     *  Recreate a picture that was serialized into a buffer. If the creation requires bitmap
+     *  decoding, the decoder must be set on the SkReadBuffer parameter by calling
+     *  SkReadBuffer::setBitmapDecoder() before calling SkPicture::CreateFromBuffer().
+     *  @param SkReadBuffer Serialized picture data.
+     *  @return A new SkPicture representing the serialized data, or NULL if the buffer is
+     *          invalid.
+     */
+    static SkPicture* CreateFromBuffer(SkReadBuffer&);
 
     virtual ~SkPicture();
 
@@ -185,6 +195,11 @@
      *  encoder will never be called with a NULL pixelRefOffset.
      */
     void serialize(SkWStream*, EncodeBitmap encoder = NULL) const;
+
+    /**
+     *  Serialize to a buffer.
+     */
+    void flatten(SkWriteBuffer&) const;
 
     /**
      * Returns true if any bitmaps may be produced when this SkPicture
@@ -223,7 +238,8 @@
     // V17: SkPixelRef now writes SkImageInfo
     // V18: SkBitmap now records x,y for its pixelref origin, instead of offset.
     // V19: encode matrices and regions into the ops stream
-    static const uint32_t PICTURE_VERSION = 19;
+    // V20: added bool to SkPictureImageFilter's serialization (to allow SkPicture serialization)
+    static const uint32_t PICTURE_VERSION = 20;
 
     // fPlayback, fRecord, fWidth & fHeight are protected to allow derived classes to
     // install their own SkPicturePlayback-derived players,SkPictureRecord-derived
@@ -245,7 +261,10 @@
     // will be ready to be parsed to create an SkPicturePlayback.
     // If false is returned, SkPictInfo is unmodified.
     static bool StreamIsSKP(SkStream*, SkPictInfo*);
+    static bool BufferIsSKP(SkReadBuffer&, SkPictInfo*);
 private:
+    void createHeader(void* header) const;
+
     friend class SkFlatPicture;
     friend class SkPicturePlayback;