Fix pacer issue with low latency mode (#75)

Author: taste1981

modules/pacing/paced_sender.cc

@@ -40,10 +40,8 @@ PacedSender::PacedSender(Clock* clock,
                          ProcessThread* process_thread)
     : low_latency_mode_(field_trial::IsEnabled("OWT-LowLatencyMode")),
       process_mode_(
-          (field_trials != nullptr &&
-           absl::StartsWith(field_trials->Lookup("OWT-LowLatencyMode"),
-                            "Enabled"))
-              ? PacingController::ProcessMode::kRealtime
+          low_latency_mode_?
+                PacingController::ProcessMode::kRealtime
               : PacingController::ProcessMode::kPeriodic),
       pacing_controller_(clock,
                          static_cast<PacingController::PacketSender*>(this),
@@ -207,8 +205,7 @@ void PacedSender::MaybeWakupProcessThread() {
   // Tell the process thread to call our TimeUntilNextProcess() method to get
   // a new time for when to call Process().
   if (process_thread_ &&
-      (process_mode_ == PacingController::ProcessMode::kDynamic||
-       process_mode_ == PacingController::ProcessMode::kRealtime)) {
+      (process_mode_ == PacingController::ProcessMode::kDynamic)) {
     process_thread_->WakeUp(&module_proxy_);
   }
 }

modules/utility/source/process_thread_impl.cc

@@ -86,7 +86,6 @@ void ProcessThreadImpl::Start() {
 }
 
 void ProcessThreadImpl::StartWithHighPriority() {
-  RTC_DCHECK(thread_checker_.CalledOnValidThread());
   RTC_DCHECK(!thread_.get());
   if (thread_.get())
     return;
@@ -96,10 +95,9 @@ void ProcessThreadImpl::StartWithHighPriority() {
   for (ModuleCallback& m : modules_)
     m.module->ProcessThreadAttached(this);
 
-  thread_.reset(
-      new rtc::PlatformThread(&ProcessThreadImpl::Run, this, thread_name_));
+  thread_.reset(new rtc::PlatformThread(&ProcessThreadImpl::Run, this,
+                                        thread_name_, rtc::kRealtimePriority));
   thread_->Start();
-  thread_->SetPriority(rtc::kRealtimePriority);
 }
 
 void ProcessThreadImpl::Stop() {