Reland the CL to remove candidates when doing continual gathering

webrtc/p2p/base/p2ptransportchannel.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 74 matching lines @@
                          const std::string& ice_pwd) override;
   void SetRemoteIceCredentials(const std::string& ice_ufrag,
                                const std::string& ice_pwd) override;
   void SetRemoteIceMode(IceMode mode) override;
   void Connect() override;
   void MaybeStartGathering() override;
   IceGatheringState gathering_state() const override {
     return gathering_state_;
   }
   void AddRemoteCandidate(const Candidate& candidate) override;
+  void RemoveRemoteCandidate(const Candidate& candidate) override;
   // Sets the parameters in IceConfig. We do not set them blindly. Instead, we
   // only update the parameter if it is considered set in |config|. For example,
   // a negative value of receiving_timeout will be considered "not set" and we
   // will not use it to update the respective parameter in |config_|.
   void SetIceConfig(const IceConfig& config) override;
   const IceConfig& config() const;
 
   // From TransportChannel:
   int SendPacket(const char* data,
                  size_t len,
@@ skipping 219 matching lines @@
   int weak_ping_interval_ = WEAK_PING_INTERVAL;
   TransportChannelState state_ = TransportChannelState::STATE_INIT;
   IceConfig config_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(P2PTransportChannel);
 };
 
 }  // namespace cricket
 
 #endif  // WEBRTC_P2P_BASE_P2PTRANSPORTCHANNEL_H_