Reset the BWE when the network changes

webrtc/p2p/base/dtlstransportchannel.h

 /*
  *  Copyright 2011 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 198 matching lines @@
   void OnDtlsEvent(rtc::StreamInterface* stream_, int sig, int err);
   bool SetupDtls();
   bool MaybeStartDtls();
   bool HandleDtlsPacket(const char* data, size_t size);
   void OnGatheringState(TransportChannelImpl* channel);
   void OnCandidateGathered(TransportChannelImpl* channel, const Candidate& c);
   void OnCandidatesRemoved(TransportChannelImpl* channel,
                            const Candidates& candidates);
   void OnRoleConflict(TransportChannelImpl* channel);
   void OnRouteChange(TransportChannel* channel, const Candidate& candidate);
+  void OnBestConnectionChanged(TransportChannel* channel,
+                               Connection* best_connection);

[pthatcher1, 2016/03/24 18:46:37]

I think we should move away from calling these "best connection"s and toward
calling them "selected connection"s, or even "selected candidate pair"s. 

Can you call this OnSelectedConnectionChanged?  And then call it
selected_connection?

[honghaiz3, 2016/03/24 22:37:12]

Done.

   void OnConnectionRemoved(TransportChannelImpl* channel);
   void Reconnect();
 
   rtc::Thread* worker_thread_;  // Everything should occur on this thread.
   // Underlying channel, not owned by this class.
   TransportChannelImpl* const channel_;
   rtc::scoped_ptr<rtc::SSLStreamAdapter> dtls_;  // The DTLS stream
   StreamInterfaceChannel* downward_;  // Wrapper for channel_, owned by dtls_.
   std::vector<int> srtp_ciphers_;     // SRTP ciphers to use with DTLS.
   bool dtls_active_ = false;
   rtc::scoped_refptr<rtc::RTCCertificate> local_certificate_;
   rtc::SSLRole ssl_role_;
   rtc::SSLProtocolVersion ssl_max_version_;
   rtc::Buffer remote_fingerprint_value_;
   std::string remote_fingerprint_algorithm_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(DtlsTransportChannelWrapper);
 };
 
 }  // namespace cricket
 
 #endif  // WEBRTC_P2P_BASE_DTLSTRANSPORTCHANNEL_H_