Remove candidates when doing continual gathering

webrtc/p2p/base/p2ptransportchannel.h

Index: webrtc/p2p/base/p2ptransportchannel.h
diff --git a/webrtc/p2p/base/p2ptransportchannel.h b/webrtc/p2p/base/p2ptransportchannel.h
index f2e93153432be261dc72083eb5a1ad948397d546..71334d30eb5bad0cd6478b3f7f83cbf5d9cf622e 100644
--- a/webrtc/p2p/base/p2ptransportchannel.h
+++ b/webrtc/p2p/base/p2ptransportchannel.h
@@ -88,6 +88,7 @@ class P2PTransportChannel : public TransportChannelImpl,
     return gathering_state_;
   }
   void AddRemoteCandidate(const Candidate& candidate) override;
+  void RemoveRemoteCandidate(const Candidate& candidate) override;
   // Sets the receiving timeout and gather_continually.
   // This also sets the check_receiving_delay proportionally.
   void SetIceConfig(const IceConfig& config) override;
@@ -227,6 +228,7 @@ class P2PTransportChannel : public TransportChannelImpl,
                         const std::string& remote_username,
                         bool port_muxed);
   void OnPortDestroyed(PortInterface* port);
+  void OnPortStopped(PortInterface* port);

[pthatcher1, 2016/02/10 00:01:41]

How is OnPortStopped different than OnPortDestroyed?

[honghaiz3, 2016/02/10 19:22:44]

PortStopped is triggered by network becoming inactive. 
PortDestroyed is triggered by port being deleted (by itself). 
In the former case we need to signal candidate removal. In the latter case
that's not needed (the remote candidates should have been removed by ICE
restart). 

   void OnRoleConflict(PortInterface* port);
 
   void OnConnectionStateChange(Connection* connection);