Convert Vp9 Rtp headers to frame references.

webrtc/modules/video_coding/frame_object.h

Index: webrtc/modules/video_coding/frame_object.h
diff --git a/webrtc/modules/video_coding/frame_object.h b/webrtc/modules/video_coding/frame_object.h
index c5cdd6eb1125c2a8ef5fb35c1f441f747c307c4d..2b39f06fcd65678cb1b505e56410a844e33f80f1 100644
--- a/webrtc/modules/video_coding/frame_object.h
+++ b/webrtc/modules/video_coding/frame_object.h
@@ -23,13 +23,20 @@ class FrameObject {
  public:
   static const uint8_t kMaxFrameReferences = 5;
 
+  FrameObject();
+
   virtual bool GetBitstream(uint8_t* destination) const = 0;
   virtual ~FrameObject() {}
 
+  // The tuple (|picture_id|, |spatial_layer|) uniquely identifies a frame
+  // object. For codec types that don't necessarily have picture ids they
+  // have to be constructed from the header data relevant to that codec.
   uint16_t picture_id;
+  uint8_t spatial_layer;
+
   size_t num_references;
-  std::array<uint16_t, kMaxFrameReferences> referencesr;
   uint16_t references[kMaxFrameReferences];
+  bool inter_layer_predicted;
 };
 
 class PacketBuffer;