Late initialize MediaController, for less resource i.e. ProcessThread, usage by PeerConnection.

webrtc/api/statscollector.cc

Index: webrtc/api/statscollector.cc
diff --git a/webrtc/api/statscollector.cc b/webrtc/api/statscollector.cc
index ca1548fa0d53531a6af4ea4c2a5b69d4f2a4b8f9..95d1b9933687fb4fc9f19750733a20a85dbf9069 100644
--- a/webrtc/api/statscollector.cc
+++ b/webrtc/api/statscollector.cc
@@ -358,17 +358,18 @@ StatsCollector::StatsCollector(PeerConnection* pc)
 }
 
 StatsCollector::~StatsCollector() {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
 }
 
 double StatsCollector::GetTimeNow() {
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
   return rtc::Timing::WallTimeNow() * rtc::kNumMillisecsPerSec;
 }
 
 // Adds a MediaStream with tracks that can be used as a |selector| in a call
 // to GetStats.
 void StatsCollector::AddStream(MediaStreamInterface* stream) {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
   RTC_DCHECK(stream != NULL);
 
   CreateTrackReports<AudioTrackVector>(stream->GetAudioTracks(),
@@ -379,7 +380,7 @@ void StatsCollector::AddStream(MediaStreamInterface* stream) {
 
 void StatsCollector::AddLocalAudioTrack(AudioTrackInterface* audio_track,
                                         uint32_t ssrc) {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
   RTC_DCHECK(audio_track != NULL);
 #if (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON))
   for (const auto& track : local_audio_tracks_)
@@ -401,6 +402,7 @@ void StatsCollector::AddLocalAudioTrack(AudioTrackInterface* audio_track,
 
 void StatsCollector::RemoveLocalAudioTrack(AudioTrackInterface* audio_track,
                                            uint32_t ssrc) {
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
   RTC_DCHECK(audio_track != NULL);
   local_audio_tracks_.erase(std::remove_if(local_audio_tracks_.begin(),
       local_audio_tracks_.end(),
@@ -411,7 +413,7 @@ void StatsCollector::RemoveLocalAudioTrack(AudioTrackInterface* audio_track,
 
 void StatsCollector::GetStats(MediaStreamTrackInterface* track,
                               StatsReports* reports) {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
   RTC_DCHECK(reports != NULL);
   RTC_DCHECK(reports->empty());
 
@@ -451,7 +453,7 @@ void StatsCollector::GetStats(MediaStreamTrackInterface* track,
 
 void
 StatsCollector::UpdateStats(PeerConnectionInterface::StatsOutputLevel level) {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
   double time_now = GetTimeNow();
   // Calls to UpdateStats() that occur less than kMinGatherStatsPeriod number of
   // ms apart will be ignored.
@@ -482,7 +484,7 @@ StatsReport* StatsCollector::PrepareReport(
     uint32_t ssrc,
     const StatsReport::Id& transport_id,
     StatsReport::Direction direction) {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
   StatsReport::Id id(StatsReport::NewIdWithDirection(
       local ? StatsReport::kStatsReportTypeSsrc
             : StatsReport::kStatsReportTypeRemoteSsrc,
@@ -521,7 +523,7 @@ StatsReport* StatsCollector::PrepareReport(
 
 StatsReport* StatsCollector::AddOneCertificateReport(
     const rtc::SSLCertificate* cert, const StatsReport* issuer) {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
 
   // TODO(bemasc): Move this computation to a helper class that caches these
   // values to reduce CPU use in GetStats.  This will require adding a fast
@@ -564,7 +566,7 @@ StatsReport* StatsCollector::AddOneCertificateReport(
 
 StatsReport* StatsCollector::AddCertificateReports(
     const rtc::SSLCertificate* cert) {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
   // Produces a chain of StatsReports representing this certificate and the rest
   // of its chain, and adds those reports to |reports_|.  The return value is
   // the id of the leaf report.  The provided cert must be non-null, so at least
@@ -592,6 +594,7 @@ StatsReport* StatsCollector::AddConnectionInfoReport(
     const std::string& content_name, int component, int connection_id,
     const StatsReport::Id& channel_report_id,
     const cricket::ConnectionInfo& info) {
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
   StatsReport::Id id(StatsReport::NewCandidatePairId(content_name, component,
                                                      connection_id));
   StatsReport* report = reports_.ReplaceOrAddNew(id);
@@ -639,6 +642,7 @@ StatsReport* StatsCollector::AddConnectionInfoReport(
 StatsReport* StatsCollector::AddCandidateReport(
     const cricket::Candidate& candidate,
     bool local) {
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
   StatsReport::Id id(StatsReport::NewCandidateId(local, candidate.id()));
   StatsReport* report = reports_.Find(id);
   if (!report) {
@@ -664,7 +668,7 @@ StatsReport* StatsCollector::AddCandidateReport(
 }
 
 void StatsCollector::ExtractSessionInfo() {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
 
   // Extract information from the base session.
   StatsReport::Id id(StatsReport::NewTypedId(
@@ -757,7 +761,7 @@ void StatsCollector::ExtractSessionInfo() {
 }
 
 void StatsCollector::ExtractVoiceInfo() {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
 
   if (!pc_->session()->voice_channel()) {
     return;
@@ -790,7 +794,7 @@ void StatsCollector::ExtractVoiceInfo() {
 
 void StatsCollector::ExtractVideoInfo(
     PeerConnectionInterface::StatsOutputLevel level) {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
 
   if (!pc_->session()->video_channel())
     return;
@@ -827,7 +831,7 @@ void StatsCollector::ExtractVideoInfo(
 }
 
 void StatsCollector::ExtractDataInfo() {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
 
   rtc::Thread::ScopedDisallowBlockingCalls no_blocking_calls;
 
@@ -847,14 +851,14 @@ void StatsCollector::ExtractDataInfo() {
 StatsReport* StatsCollector::GetReport(const StatsReport::StatsType& type,
                                        const std::string& id,
                                        StatsReport::Direction direction) {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
   RTC_DCHECK(type == StatsReport::kStatsReportTypeSsrc ||
              type == StatsReport::kStatsReportTypeRemoteSsrc);
   return reports_.Find(StatsReport::NewIdWithDirection(type, id, direction));
 }
 
 void StatsCollector::UpdateStatsFromExistingLocalAudioTracks() {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
   // Loop through the existing local audio tracks.
   for (const auto& it : local_audio_tracks_) {
     AudioTrackInterface* track = it.first;
@@ -882,7 +886,7 @@ void StatsCollector::UpdateStatsFromExistingLocalAudioTracks() {
 
 void StatsCollector::UpdateReportFromAudioTrack(AudioTrackInterface* track,
                                                 StatsReport* report) {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
   RTC_DCHECK(track != NULL);
 
   // Don't overwrite report values if they're not available.
@@ -908,7 +912,7 @@ void StatsCollector::UpdateReportFromAudioTrack(AudioTrackInterface* track,
 bool StatsCollector::GetTrackIdBySsrc(uint32_t ssrc,
                                       std::string* track_id,
                                       StatsReport::Direction direction) {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
   if (direction == StatsReport::kSend) {
     if (!pc_->session()->GetLocalTrackIdBySsrc(ssrc, track_id)) {
       LOG(LS_WARNING) << "The SSRC " << ssrc
@@ -928,7 +932,7 @@ bool StatsCollector::GetTrackIdBySsrc(uint32_t ssrc,
 }
 
 void StatsCollector::UpdateTrackReports() {
-  RTC_DCHECK(pc_->session()->signaling_thread()->IsCurrent());
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
 
   rtc::Thread::ScopedDisallowBlockingCalls no_blocking_calls;
 
@@ -939,6 +943,7 @@ void StatsCollector::UpdateTrackReports() {
 }
 
 void StatsCollector::ClearUpdateStatsCacheForTest() {
+  RTC_DCHECK(signal_thread_checker_.CalledOnValidThread());
   stats_gathering_started_ = 0;
 }