Reset the BWE when the network changes

webrtc/call.h

Index: webrtc/call.h
diff --git a/webrtc/call.h b/webrtc/call.h
index 313c5e58c16f49446c8d6fbcdaa92950179628a8..67ad3f3b0b9c97a5bb3febe16433d1fcfc5c7477 100644
--- a/webrtc/call.h
+++ b/webrtc/call.h
@@ -135,6 +135,8 @@ class Call {
       const Config::BitrateConfig& bitrate_config) = 0;
   virtual void SignalNetworkState(NetworkState state) = 0;
 
+  virtual void OnNetworkChanged(int local_net_id, int remote_net_id) = 0;

[pthatcher1, 2016/03/16 21:22:03]

To save ourselves trouble later when we want to add more information here (such
as 2g/3g/4g/wifi, or other info), I think it would make sense to pass a struct. 
Perhaps something like:

struct NetworkRoute {
  // False if there is no route currently.
  bool connected;
  // Unset if either there is no route (in which case !connected)
  // or the network ID is unknown.
  Optional<int> local_network_id;
  Optional<int> remote_network_id;
}

And then have could include old and new and save the handler from storing the
old:

OnNetworkRouteChanged(const NetworkRoute& old_route, const NetworkRoute&
new_route);

[honghaiz3, 2016/03/17 03:38:26]

I now just pass the Connection (CandidatePair), which should include every
information we need.

+
   virtual void OnSentPacket(const rtc::SentPacket& sent_packet) = 0;
 
   virtual ~Call() {}