Fix code style and gyp files in cast to build cast_unittest

media/cast/rtp_sender/rtp_packetizer/rtp_packetizer.gyp

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'cast_rtp_packetizer',
       'type': 'static_library',
       'include_dirs': [
         '<(DEPTH)/',
         '<(DEPTH)/third_party/',
         '<(DEPTH)/third_party/webrtc/',
       ],
       'sources': [
         'rtp_packetizer.cc',
         'rtp_packetizer.h',
+        'rtp_packetizer_config.cc',
+        'rtp_packetizer_config.h',
       ], # source
       'dependencies': [
         '<(DEPTH)/base/base.gyp:base',
         '<(DEPTH)/net/net.gyp:*',
       ],
     },
   ],
 }