Remove candidates when doing continual gathering

webrtc/p2p/base/dtlstransportchannel.cc

Index: webrtc/p2p/base/dtlstransportchannel.cc
diff --git a/webrtc/p2p/base/dtlstransportchannel.cc b/webrtc/p2p/base/dtlstransportchannel.cc
index d6b5bce723d48282c0f19854330a89afc0c4e1db..ee9ea34939c6ead028534caa58acb6b51b4feab6 100644
--- a/webrtc/p2p/base/dtlstransportchannel.cc
+++ b/webrtc/p2p/base/dtlstransportchannel.cc
@@ -110,6 +110,8 @@ DtlsTransportChannelWrapper::DtlsTransportChannelWrapper(
       this, &DtlsTransportChannelWrapper::OnGatheringState);
   channel_->SignalCandidateGathered.connect(
       this, &DtlsTransportChannelWrapper::OnCandidateGathered);
+  channel_->SignalCandidatesRemoved.connect(
+      this, &DtlsTransportChannelWrapper::OnCandidatesRemoved);
   channel_->SignalRoleConflict.connect(this,
       &DtlsTransportChannelWrapper::OnRoleConflict);
   channel_->SignalRouteChange.connect(this,
@@ -610,6 +612,13 @@ void DtlsTransportChannelWrapper::OnCandidateGathered(
   SignalCandidateGathered(this, c);
 }
 
+void DtlsTransportChannelWrapper::OnCandidatesRemoved(
+    TransportChannelImpl* channel,
+    const Candidates& cc) {
+  ASSERT(channel == channel_);
+  SignalCandidatesRemoved(this, cc);
+}
+
 void DtlsTransportChannelWrapper::OnRoleConflict(
     TransportChannelImpl* channel) {
   ASSERT(channel == channel_);