Add generic interfaces for the sinks of the media stream audio track

content/content_renderer.gypi

 # 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.
 
 {
   'dependencies': [
     '../jingle/jingle.gyp:jingle_glue',
     '../media/media.gyp:media',
     '../net/net.gyp:net',
     '../skia/skia.gyp:skia',
@@ skipping 562 matching lines @@
     }],
     ['enable_webrtc==1', {
       'dependencies': [
         '../third_party/libjingle/libjingle.gyp:libjingle_webrtc',
         '../third_party/libjingle/libjingle.gyp:libpeerconnection',
         '../third_party/webrtc/modules/modules.gyp:audio_device',
         '../third_party/webrtc/modules/modules.gyp:audio_processing',
         '<(DEPTH)/crypto/crypto.gyp:crypto',
       ],
       'sources': [
+        'public/renderer/media_stream_audio_sink.h'

[no longer working on chromium, 2013/11/27 13:36:20]

Note, I put them under enable_webrtc==1 otherwise it won't compile because some
of the dependencies are under the flag.

We will try getting rid of the "enable_webrtc" flag for getUserMedia as
follow-ups.

+        'public/renderer/media_stream_audio_sink.cc'
         'public/renderer/webrtc_log_message_delegate.h',
         'renderer/media/media_stream_audio_processor.cc',
         'renderer/media/media_stream_audio_processor.h',
         'renderer/media/media_stream_audio_processor_options.cc',
         'renderer/media/media_stream_audio_processor_options.h',
         'renderer/media/media_stream_center.cc',
         'renderer/media/media_stream_dependency_factory.cc',
         'renderer/media/media_stream_dispatcher.cc',
         'renderer/media/media_stream_impl.cc',
         'renderer/media/media_stream_registry_interface.h',
@@ skipping 135 matching lines @@
     }],
   ],
   'target_conditions': [
     ['OS=="android"', {
       'sources/': [
         ['include', '^renderer/render_view_linux\\.cc$'],
       ],
     }],
   ],
 }