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

webrtc/logging/rtc_event_log/rtc_event_log.h

Index: webrtc/logging/rtc_event_log/rtc_event_log.h
diff --git a/webrtc/logging/rtc_event_log/rtc_event_log.h b/webrtc/logging/rtc_event_log/rtc_event_log.h
index dc3351120c89d458222e715ad0a872f5804dc2c7..8e1ec2128934f58a6ee178f2e923887416385342 100644
--- a/webrtc/logging/rtc_event_log/rtc_event_log.h
+++ b/webrtc/logging/rtc_event_log/rtc_event_log.h
@@ -170,6 +170,13 @@ class RtcEventLog {
   virtual void LogProbeResultFailure(int id,
                                      ProbeFailureReason failure_reason) = 0;
 
+  // Logs the result of a host lookup.
+  // if error =  0 - no error
+  //    error = -1 - generic error
+  //    else       - is given by underlying resolver
+  virtual void LogHostLookupResult(int error,
+                                   int64_t elapsed_time_in_milliseconds) = 0;
+
   // Reads an RtcEventLog file and returns true when reading was successful.
   // The result is stored in the given EventStream object.
   // The order of the events in the EventStream is implementation defined.
@@ -224,6 +231,9 @@ class RtcEventLogNullImpl : public RtcEventLog {
   void LogProbeResultSuccess(int id, int bitrate_bps) override{};
   void LogProbeResultFailure(int id,
                              ProbeFailureReason failure_reason) override{};
+
+  void LogHostLookupResult(int error,
+                           int64_t elapsed_time_in_milliseconds) override {}
 };
 
 }  // namespace webrtc