Add logging of host lookups made by TurnPort to the RtcEventLog.

webrtc/logging/rtc_event_log/mock/mock_rtc_event_log.h

 /*
  *  Copyright (c) 2016 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 58 matching lines @@
 
   MOCK_METHOD1(LogAudioNetworkAdaptation,
                void(const AudioEncoderRuntimeConfig& config));
 
   MOCK_METHOD4(LogProbeClusterCreated,
                void(int id, int bitrate_bps, int min_probes, int min_bytes));
 
   MOCK_METHOD2(LogProbeResultSuccess, void(int id, int bitrate_bps));
   MOCK_METHOD2(LogProbeResultFailure,
                void(int id, ProbeFailureReason failure_reason));
+
+  MOCK_METHOD2(LogHostLookupResult,
+               void(int error,
+                    int64_t time_ms));
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_LOGGING_RTC_EVENT_LOG_MOCK_MOCK_RTC_EVENT_LOG_H_