Use continual gathering to restore backup connections

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 ada3ecfb8bb2deeb6bc5d9120eb1647d7cd1a1da..6ee85f024eb8e4ceb57b87618254a64d13e5d150 100644
--- a/webrtc/p2p/base/p2ptransportchannel.h
+++ b/webrtc/p2p/base/p2ptransportchannel.h
@@ -234,6 +234,8 @@ class P2PTransportChannel : public TransportChannelImpl,
   void OnPortReady(PortAllocatorSession *session, PortInterface* port);
   void OnCandidatesReady(PortAllocatorSession *session,
                          const std::vector<Candidate>& candidates);
+  void OnCandidatesRemoved(PortAllocatorSession* session,
+                           const std::vector<Candidate>& candidates);
   void OnCandidatesAllocationDone(PortAllocatorSession* session);
   void OnUnknownAddress(PortInterface* port,
                         const rtc::SocketAddress& addr,
@@ -241,8 +243,12 @@ class P2PTransportChannel : public TransportChannelImpl,
                         IceMessage* stun_msg,
                         const std::string& remote_username,
                         bool port_muxed);
+
+  // When a port is destroyed or closed, remove it from our list of ports to
+  // use for connection attempts.
   void OnPortDestroyed(PortInterface* port);
-  void OnPortNetworkInactive(PortInterface* port);
+  void OnPortClosed(PortInterface* port);
+  bool RemovePort(PortInterface* port);
   void OnRoleConflict(PortInterface* port);
 
   void OnConnectionStateChange(Connection* connection);
@@ -257,6 +263,7 @@ class P2PTransportChannel : public TransportChannelImpl,
   void OnMessage(rtc::Message* pmsg) override;
   void OnSort();
   void OnCheckAndPing();
+  void OnRegatherOnFailedNetworks();
 
   void PruneConnections();
   Connection* best_nominated_connection() const;
@@ -332,6 +339,7 @@ class P2PTransportChannel : public TransportChannelImpl,
   TransportChannelState state_ = TransportChannelState::STATE_INIT;
   IceConfig config_;
   int last_sent_packet_id_ = -1;  // -1 indicates no packet was sent before.
+  std::vector<Candidate> candidates_to_remove_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(P2PTransportChannel);
 };