Make CodecType conversion functions non-optional.

webrtc/modules/video_coding/packet.cc

 /*
  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 116 matching lines @@
       } else if (is_first_packet_in_frame) {
         completeNALU = kNaluStart;
       } else if (markerBit) {
         completeNALU = kNaluEnd;
       } else {
         completeNALU = kNaluIncomplete;
       }
       codec = kVideoCodecH264;
       return;
     case kRtpVideoGeneric:
+      codec = kVideoCodecGeneric;
+      return;
     case kRtpVideoNone:
       codec = kVideoCodecUnknown;
       return;
   }
 }
 
 }  // namespace webrtc