Base A/V synchronization on sync_labels.

talk/media/webrtc/webrtcvoiceengine.h

Index: talk/media/webrtc/webrtcvoiceengine.h
diff --git a/talk/media/webrtc/webrtcvoiceengine.h b/talk/media/webrtc/webrtcvoiceengine.h
index 35f2dbc93ef0bfb319b283aa934762ae2da07ecd..7e0e613884f1bd98383ff1be550407bb3650c69e 100644
--- a/talk/media/webrtc/webrtcvoiceengine.h
+++ b/talk/media/webrtc/webrtcvoiceengine.h
@@ -402,7 +402,7 @@ class WebRtcVoiceMediaChannel : public VoiceMediaChannel,
 
   bool SetHeaderExtension(ExtensionSetterFunction setter, int channel_id,
                           const RtpHeaderExtension* extension);
-  void TryAddAudioRecvStream(uint32 ssrc);
+  void TryAddAudioRecvStream(uint32 ssrc, WebRtcVoiceChannelRenderer* channel);
   void TryRemoveAudioRecvStream(uint32 ssrc);
 
   bool SetChannelRecvRtpHeaderExtensions(
@@ -447,7 +447,7 @@ class WebRtcVoiceMediaChannel : public VoiceMediaChannel,
   // receive_channels_ can be read from WebRtc callback thread.  Access from
   // the WebRtc thread must be synchronized with edits on the worker thread.
   // Reads on the worker thread are ok.
-  //
+  std::map<int, std::string> sync_labels_;
   std::vector<RtpHeaderExtension> receive_extensions_;
   std::vector<webrtc::RtpExtension> recv_rtp_extensions_;