Remove candidates when doing continual gathering

webrtc/api/peerconnection.h

Index: webrtc/api/peerconnection.h
diff --git a/webrtc/api/peerconnection.h b/webrtc/api/peerconnection.h
index e4fcdf075a0dc025f337e14f473d7c9eeb6203d5..b388dfb84774f0516010ecd835c43752321cd861 100644
--- a/webrtc/api/peerconnection.h
+++ b/webrtc/api/peerconnection.h
@@ -130,6 +130,8 @@ class PeerConnection : public PeerConnectionInterface,
   bool SetConfiguration(
       const PeerConnectionInterface::RTCConfiguration& config) override;
   bool AddIceCandidate(const IceCandidateInterface* candidate) override;
+  bool RemoveIceCandidates(
+      const std::vector<cricket::Candidate>& candidates) override;
 
   void RegisterUMAObserver(UMAObserver* observer) override;
 
@@ -184,6 +186,8 @@ class PeerConnection : public PeerConnectionInterface,
   void OnIceConnectionChange(IceConnectionState new_state) override;
   void OnIceGatheringChange(IceGatheringState new_state) override;
   void OnIceCandidate(const IceCandidateInterface* candidate) override;
+  void OnIceCandidatesRemoved(
+      const std::vector<cricket::Candidate>& candidates) override;
   void OnIceConnectionReceivingChange(bool receiving) override;
 
   // Signals from WebRtcSession.