Adding ThreadChecker validation to d'tors for protocol classes

remoting/protocol/webrtc_video_stream.cc

Index: remoting/protocol/webrtc_video_stream.cc
diff --git a/remoting/protocol/webrtc_video_stream.cc b/remoting/protocol/webrtc_video_stream.cc
index 72835251cd465d78eef2627df6787903b277e166..0167d3a61d2d80e12ed7f80777f96d5758c0b53c 100644
--- a/remoting/protocol/webrtc_video_stream.cc
+++ b/remoting/protocol/webrtc_video_stream.cc
@@ -51,6 +51,7 @@ WebrtcVideoStream::WebrtcVideoStream()
     : video_stats_dispatcher_(kStreamLabel), weak_factory_(this) {}
 
 WebrtcVideoStream::~WebrtcVideoStream() {
+  DCHECK(thread_checker_.CalledOnValidThread());
   if (stream_) {
     for (const auto& track : stream_->GetVideoTracks()) {
       stream_->RemoveTrack(track.get());