This CL adds methods to manipulate RTP header extension, particularly

third_party/libjingle/libjingle.gyp

 # Copyright (c) 2012 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.
 
 {
   'includes': [
     '../../build/win_precompile.gypi',
   ],
   'variables': {
     'enabled_libjingle_device_manager%': 0,
@@ skipping 417 matching lines @@
             '<(libjingle_source)/talk/session/media/audiomonitor.cc',
             '<(libjingle_source)/talk/session/media/audiomonitor.h',
             '<(libjingle_source)/talk/session/media/call.cc',
             '<(libjingle_source)/talk/session/media/call.h',
             '<(libjingle_source)/talk/session/media/channel.cc',
             '<(libjingle_source)/talk/session/media/channel.h',
             '<(libjingle_source)/talk/session/media/channelmanager.cc',
             '<(libjingle_source)/talk/session/media/channelmanager.h',
             '<(libjingle_source)/talk/session/media/currentspeakermonitor.cc',
             '<(libjingle_source)/talk/session/media/currentspeakermonitor.h',
+            '<(libjingle_source)/talk/session/media/externalhmac.cc',
+            '<(libjingle_source)/talk/session/media/externalhmac.h',
             '<(libjingle_source)/talk/session/media/mediamessages.cc',
             '<(libjingle_source)/talk/session/media/mediamessages.h',
             '<(libjingle_source)/talk/session/media/mediamonitor.cc',
             '<(libjingle_source)/talk/session/media/mediamonitor.h',
             '<(libjingle_source)/talk/session/media/mediasession.cc',
             '<(libjingle_source)/talk/session/media/mediasession.h',
             '<(libjingle_source)/talk/session/media/mediasessionclient.cc',
             '<(libjingle_source)/talk/session/media/mediasessionclient.h',
             '<(libjingle_source)/talk/session/media/mediasink.h',
             '<(libjingle_source)/talk/session/media/rtcpmuxfilter.cc',
@@ skipping 188 matching lines @@
               # in this directory and not lib.target as will otherwise be
               # the case with make builds.
               'product_dir': '<(PRODUCT_DIR)/lib',
             }],
           ],
         },  # target libpeerconnection
       ],
     }],
   ],
 }