Add empty placeholder files for remote audio tracks.

talk/libjingle.gyp

 #
 # libjingle
 # Copyright 2012 Google Inc.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are met:
 #
 #  1. Redistributions of source code must retain the above copyright notice,
 #     this list of conditions and the following disclaimer.
 #  2. Redistributions in binary form must reproduce the above copyright notice,
@@ skipping 744 matching lines @@
         'app/webrtc/peerconnectionfactory.cc',
         'app/webrtc/peerconnectionfactory.h',
         'app/webrtc/peerconnectionfactoryproxy.h',
         'app/webrtc/peerconnectioninterface.h',
         'app/webrtc/peerconnectionproxy.h',
         'app/webrtc/portallocatorfactory.cc',
         'app/webrtc/portallocatorfactory.h',
         'app/webrtc/proxy.h',
         'app/webrtc/remoteaudiosource.cc',
         'app/webrtc/remoteaudiosource.h',
+        'app/webrtc/remoteaudiotrack.cc',
+        'app/webrtc/remoteaudiotrack.h',
         'app/webrtc/remotevideocapturer.cc',
         'app/webrtc/remotevideocapturer.h',
         'app/webrtc/rtpreceiver.cc',
         'app/webrtc/rtpreceiver.h',
         'app/webrtc/rtpreceiverinterface.h',
         'app/webrtc/rtpsender.cc',
         'app/webrtc/rtpsender.h',
         'app/webrtc/rtpsenderinterface.h',
         'app/webrtc/sctputils.cc',
         'app/webrtc/sctputils.h',
@@ skipping 21 matching lines @@
         ['OS=="android" and build_with_chromium==0', {
           'sources': [
             'app/webrtc/androidvideocapturer.h',
             'app/webrtc/androidvideocapturer.cc',
            ],
         }],
       ],
     },  # target libjingle_peerconnection
   ],
 }