[Cast] Clean-up RtpCastHeader and RtpParser, removing the last WebRTC dependency.

media/cast/framer/frame_id_map.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/cast/framer/frame_id_map.h"
 
 #include "base/logging.h"
 #include "media/cast/rtp_receiver/rtp_receiver_defines.h"
 
 namespace media {
@@ skipping 44 matching lines @@
 FrameIdMap::FrameIdMap()
     : waiting_for_key_(true),
       last_released_frame_(kStartFrameId),
       newest_frame_id_(kStartFrameId) {}
 
 FrameIdMap::~FrameIdMap() {}
 
 PacketType FrameIdMap::InsertPacket(const RtpCastHeader& rtp_header) {
   uint32 frame_id = rtp_header.frame_id;
   uint32 reference_frame_id;
-  if (rtp_header.is_reference) {
-    reference_frame_id = rtp_header.reference_frame_id;
-  } else {
-    reference_frame_id = static_cast<uint32>(frame_id - 1);
-  }
+  reference_frame_id = rtp_header.reference_frame_id;
 
   if (rtp_header.is_key_frame && waiting_for_key_) {
     last_released_frame_ = static_cast<uint32>(frame_id - 1);
     waiting_for_key_ = false;
   }
 
   VLOG(3) << "InsertPacket frame:" << frame_id
           << " packet:" << static_cast<int>(rtp_header.packet_id)
           << " max packet:" << static_cast<int>(rtp_header.max_packet_id);
 
@@ skipping 170 matching lines @@
   // Current frame is not necessarily referencing the last frame.
   // Do we have the reference frame?
   if (IsOlderFrameId(frame->referenced_frame_id(), last_released_frame_)) {
     return true;
   }
   return frame->referenced_frame_id() == last_released_frame_;
 }
 
 }  //  namespace cast
 }  //  namespace media