Reland of Free SCTP data channels asynchronously in PeerConnection.

talk/app/webrtc/peerconnection.h

 /*
  * 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 356 matching lines @@
   // These lists store track info seen in local/remote descriptions.
   TrackInfos remote_audio_tracks_;
   TrackInfos remote_video_tracks_;
   TrackInfos local_audio_tracks_;
   TrackInfos local_video_tracks_;
 
   SctpSidAllocator sid_allocator_;
   // label -> DataChannel
   std::map<std::string, rtc::scoped_refptr<DataChannel>> rtp_data_channels_;
   std::vector<rtc::scoped_refptr<DataChannel>> sctp_data_channels_;
+  std::vector<rtc::scoped_refptr<DataChannel>> sctp_data_channels_to_free_;
 
   bool remote_peer_supports_msid_ = false;
   rtc::scoped_ptr<RemoteMediaStreamFactory> remote_stream_factory_;
 
   std::vector<rtc::scoped_refptr<RtpSenderInterface>> senders_;
   std::vector<rtc::scoped_refptr<RtpReceiverInterface>> receivers_;
 
   // The session_ scoped_ptr is declared at the bottom of PeerConnection
   // because its destruction fires signals (such as VoiceChannelDestroyed)
   // which will trigger some final actions in PeerConnection...
   rtc::scoped_ptr<WebRtcSession> session_;
   // ... But stats_ depends on session_ so it should be destroyed even earlier.
   rtc::scoped_ptr<StatsCollector> stats_;
 };
 
 }  // namespace webrtc
 
 #endif  // TALK_APP_WEBRTC_PEERCONNECTION_H_