Create a new connection if a candidate reuses an address

webrtc/p2p/base/port.h

Index: webrtc/p2p/base/port.h
diff --git a/webrtc/p2p/base/port.h b/webrtc/p2p/base/port.h
index 704fbb7a65416d42fab37cd8858a43fcdcc0292d..21203572b1e0d88a1bd89bdff09544131d5888b4 100644
--- a/webrtc/p2p/base/port.h
+++ b/webrtc/p2p/base/port.h
@@ -316,8 +316,10 @@ class Port : public PortInterface, public rtc::MessageHandler,
                   uint32_t relay_preference,
                   bool final);
 
-  // Adds the given connection to the list.  (Deleting removes them.)
-  void AddConnection(Connection* conn);
+  // Adds the given connection to the map keyed by the remote candidate address.
+  // If an existing connection has the same address, the existing one will be
+  // replaced and destroyed.
+  void AddOrReplaceConnection(Connection* conn);
 
   // Called when a packet is received from an unknown address that is not
   // currently a connection.  If this is an authenticated STUN binding request,
@@ -346,6 +348,9 @@ class Port : public PortInterface, public rtc::MessageHandler,
     return rtc::DSCP_NO_CHANGE;
   }
 
+  // Extra work to be done in subclasses when a connection is destroyed.
+  virtual void HandleConnectionDestroyed(Connection* conn) {}
+
  private:
   void Construct();
   // Called when one of our connections deletes itself.