Adding IceConfig option to assume TURN/TURN candidate pairs will work.

webrtc/p2p/base/relayport.h

 /*
  *  Copyright 2004 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 38 matching lines @@
   ~RelayPort() override;
 
   void AddServerAddress(const ProtocolAddress& addr);
   void AddExternalAddress(const ProtocolAddress& addr);
 
   const std::vector<OptionValue>& options() const { return options_; }
   bool HasMagicCookie(const char* data, size_t size);
 
   void PrepareAddress() override;
   Connection* CreateConnection(const Candidate& address,
-                               CandidateOrigin origin) override;
+                               CandidateOrigin origin,
+                               const IceConfig& config) override;
   int SetOption(rtc::Socket::Option opt, int value) override;
   int GetOption(rtc::Socket::Option opt, int* value) override;
   int GetError() override;
   bool SupportsProtocol(const std::string& protocol) const override {
     // Relay port may create both TCP and UDP connections.
     return true;
   }
 
   const ProtocolAddress * ServerAddress(size_t index) const;
   bool IsReady() { return ready_; }
@@ skipping 39 matching lines @@
   std::vector<ProtocolAddress> external_addr_;
   bool ready_;
   std::vector<RelayEntry*> entries_;
   std::vector<OptionValue> options_;
   int error_;
 };
 
 }  // namespace cricket
 
 #endif  // WEBRTC_P2P_BASE_RELAYPORT_H_