Log DTLS state changes to RtcEventLog

Bug: webrtc:9972
Change-Id: Icb2cdda87c1c42607ed06653e053699532f25e84
Reviewed-on: https://webrtc-review.googlesource.com/c/111023
Commit-Queue: Zach Stein <zstein@webrtc.org>
Reviewed-by: Qingsi Wang <qingsi@webrtc.org>
Reviewed-by: Björn Terelius <terelius@webrtc.org>
Reviewed-by: Steve Anton <steveanton@webrtc.org>
Reviewed-by: Elad Alon <eladalon@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25832}
diff --git a/logging/BUILD.gn b/logging/BUILD.gn
index ebfad5c..0688485 100644
--- a/logging/BUILD.gn
+++ b/logging/BUILD.gn
@@ -400,6 +400,8 @@
 
 rtc_source_set("ice_log") {
   sources = [
+    "rtc_event_log/events/rtc_event_dtls_transport_state.cc",
+    "rtc_event_log/events/rtc_event_dtls_transport_state.h",
     "rtc_event_log/events/rtc_event_ice_candidate_pair.cc",
     "rtc_event_log/events/rtc_event_ice_candidate_pair.h",
     "rtc_event_log/events/rtc_event_ice_candidate_pair_config.cc",