Request key frames to battle error propagation.

The VP8 decoder wrapper will request key frames 30 frames after seeing
a packet loss, if it hasn't received a state refresh (only possible
through key frames in this version).

For this to be possible the jitter buffer has been made aware of
picture ids to be able to detect frame losses. Legacy JB code to
handle streams without marker bits was also removed since it
conflicts with streams with FEC.

BUG=
TEST=

Review URL: http://webrtc-codereview.appspot.com/239002

git-svn-id: http://webrtc.googlecode.com/svn/trunk@774 4adac7df-926f-26a2-2b94-8c16560cd09d

src/modules/video_coding/main/source/frame_buffer.h

@@ -45,7 +45,6 @@ public:
     bool IsRetransmitted() const;
     bool IsSessionComplete() const;
     bool HaveLastPacket() const;
-    bool ForceSetHaveLastPacket();
     // Makes sure the session contain a decodable stream.
     void MakeSessionDecodable();
 
@@ -55,6 +54,8 @@ public:
     // Get highest packet sequence number in frame
     WebRtc_Word32 GetHighSeqNum() const;
 
+    int PictureId() const;
+
     // Set counted status (as counted by JB or not)
     void SetCountedFrame(bool frameCounted);
     bool GetCountedFrame() const;