Remove candidates when doing continual gathering

webrtc/p2p/base/faketransportcontroller.h

Index: webrtc/p2p/base/faketransportcontroller.h
diff --git a/webrtc/p2p/base/faketransportcontroller.h b/webrtc/p2p/base/faketransportcontroller.h
index 65c59be98d0ee93777f6454e8742ded125caf5b1..162a672c99a90583e2ecfd387bfd8994ea31ac7f 100644
--- a/webrtc/p2p/base/faketransportcontroller.h
+++ b/webrtc/p2p/base/faketransportcontroller.h
@@ -221,6 +221,9 @@ class FakeTransportChannel : public TransportChannelImpl,
   void AddRemoteCandidate(const Candidate& candidate) override {
     remote_candidates_.push_back(candidate);
   }
+
+  void RemoveRemoteCandidate(const Candidate& candidate) override {}
+
   const Candidates& remote_candidates() const { return remote_candidates_; }
 
   void OnMessage(rtc::Message* msg) override {