Added the desktop shape fields to VideoPacket.

remoting/codec/video_decoder_vp8.h

Index: remoting/codec/video_decoder_vp8.h
diff --git a/remoting/codec/video_decoder_vp8.h b/remoting/codec/video_decoder_vp8.h
index 53a720ba9b6711448e78cb52fa72b324012e7c3d..2efbd223c05396eea0878c1a3a369067a592401e 100644
--- a/remoting/codec/video_decoder_vp8.h
+++ b/remoting/codec/video_decoder_vp8.h
@@ -30,6 +30,7 @@ class VideoDecoderVp8 : public VideoDecoder {
                            uint8* image_buffer,
                            int image_stride,
                            SkRegion* output_region) OVERRIDE;
+  virtual const SkRegion* GetImageShape() OVERRIDE;
 
  private:
   enum State {
@@ -38,6 +39,14 @@ class VideoDecoderVp8 : public VideoDecoder {
     kError,
   };
 
+  // Fills the rectangle |rect| with the given ARGB color |color| in |buffer|.
+  void FillRect(uint8* buffer, int stride, const SkIRect& rect, uint32 color);
+
+  // Calculates the difference between the desktop shape regions in two
+  // consecutive frames and updates |updated_region_| and |transparent_region_|
+  // accordingly.
+  void UpdateImageShapeRegion(SkRegion* new_desktop_shape);
+
   // The internal state of the decoder.
   State state_;
 
@@ -52,6 +61,12 @@ class VideoDecoderVp8 : public VideoDecoder {
   // Output dimensions.
   SkISize screen_size_;
 
+  // The region occupied by the top level windows.
+  SkRegion desktop_shape_;
+
+  // The region that should be make transparent.
+  SkRegion transparent_region_;
+
   DISALLOW_COPY_AND_ASSIGN(VideoDecoderVp8);
 };