Log how often DTLS negotiation failed because of incompatible ciphersuites.

webrtc/p2p/base/transportcontroller.cc

 /*
  *  Copyright 2015 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 173 matching lines @@
   channel->SignalGatheringState.connect(
       this, &TransportController::OnChannelGatheringState_n);
   channel->SignalCandidateGathered.connect(
       this, &TransportController::OnChannelCandidateGathered_n);
   channel->SignalCandidatesRemoved.connect(
       this, &TransportController::OnChannelCandidatesRemoved_n);
   channel->SignalRoleConflict.connect(
       this, &TransportController::OnChannelRoleConflict_n);
   channel->SignalStateChanged.connect(
       this, &TransportController::OnChannelStateChanged_n);
+  channel->SignalDtlsHandshakeError.connect(
+      this, &TransportController::OnDtlsHandshakeError);
   channels_.insert(channels_.end(), RefCountedChannel(channel))->AddRef();
   // Adding a channel could cause aggregate state to change.
   UpdateAggregateStates_n();
   return channel;
 }
 
 void TransportController::DestroyTransportChannel_n(
     const std::string& transport_name,
     int component) {
   RTC_DCHECK(network_thread_->IsCurrent());
@@ skipping 474 matching lines @@
     new_gathering_state = kIceGatheringGathering;
   }
   if (gathering_state_ != new_gathering_state) {
     gathering_state_ = new_gathering_state;
     signaling_thread_->Post(
         RTC_FROM_HERE, this, MSG_ICEGATHERINGSTATE,
         new rtc::TypedMessageData<IceGatheringState>(new_gathering_state));
   }
 }
 
+void TransportController::OnDtlsHandshakeError(rtc::SSLHandshakeError error) {
+  SignalDtlsHandshakeError(error);
+}
+
 }  // namespace cricket