Refactor bitrate_controller, remote_bitrate_estimator and congestion_contoller for gn check

.gn

Index: .gn
diff --git a/.gn b/.gn
index 155e4a27de422a8081246836dd770a06839213b6..c82d4808b72732680802ac199c9b31cee21652db 100644
--- a/.gn
+++ b/.gn
@@ -29,6 +29,8 @@ check_targets = [
   "//webrtc/modules/audio_device/*",
   "//webrtc/modules/audio_mixer/*",
   "//webrtc/modules/audio_processing/*",
+  "//webrtc/modules/bitrate_controller/*",
+  "//webrtc/modules/congestion_controller/*",
   "//webrtc/modules/media_file/*",
   "//webrtc/modules/pacing/*",
   "//webrtc/modules/rtp_rtcp/*",
@@ -36,6 +38,7 @@ check_targets = [
   "//webrtc/modules/video_capture/*",
   "//webrtc/modules/video_coding/*",
   "//webrtc/modules/video_processing/*",
+  "//webrtc/modules/remote_bitrate_estimator/*",
   "//webrtc/stats:rtc_stats",
   "//webrtc/voice_engine",
   "//webrtc/voice_engine:level_indicator",