Remove candidates when doing continual gathering

webrtc/api/webrtcsession.h

Index: webrtc/api/webrtcsession.h
diff --git a/webrtc/api/webrtcsession.h b/webrtc/api/webrtcsession.h
index 87379abd8dfc3f7b03dee9edd62275b52875e3d7..f8097e6644adc96ef3168107e61c5d16ec00850f 100644
--- a/webrtc/api/webrtcsession.h
+++ b/webrtc/api/webrtcsession.h
@@ -25,6 +25,7 @@
 #include "webrtc/base/sslidentity.h"
 #include "webrtc/base/thread.h"
 #include "webrtc/media/base/mediachannel.h"
+#include "webrtc/p2p/base/candidate.h"
 #include "webrtc/p2p/base/transportcontroller.h"
 #include "webrtc/pc/mediasession.h"
 
@@ -81,6 +82,10 @@ class IceObserver {
   // New Ice candidate have been found.
   virtual void OnIceCandidate(const IceCandidateInterface* candidate) = 0;
 
+  // Some local ICE candidates have been removed.
+  virtual void OnIceCandidatesRemoved(
+      const cricket::Candidates& candidates) = 0;
+
   // Called whenever the state changes between receiving and not receiving.
   virtual void OnIceConnectionReceivingChange(bool receiving) {}
 
@@ -205,6 +210,8 @@ class WebRtcSession : public AudioProviderInterface,
                             std::string* err_desc);
   bool ProcessIceMessage(const IceCandidateInterface* ice_candidate);
 
+  bool RemoveRemoteIceCandidates(const cricket::Candidates& candidates);
+
   bool SetIceTransports(PeerConnectionInterface::IceTransportsType type);
 
   cricket::IceConfig ParseIceConfig(
@@ -432,6 +439,8 @@ class WebRtcSession : public AudioProviderInterface,
   void OnTransportControllerCandidatesGathered(
       const std::string& transport_name,
       const cricket::Candidates& candidates);
+  void OnTransportControllerCandidatesRemoved(
+      const cricket::Candidates& candidates);
 
   std::string GetSessionErrorMsg();