Add functionality which limits the number of bytes on the network.

webrtc/call/call.cc

Index: webrtc/call/call.cc
diff --git a/webrtc/call/call.cc b/webrtc/call/call.cc
index 41f53feee7c57ed5e42753ad9e2a78075eb8a22c..a7c85a211dbb8137d6e5560d1ab1bd64c3e85afa 100644
--- a/webrtc/call/call.cc
+++ b/webrtc/call/call.cc
@@ -435,17 +435,20 @@ Call::Call(const Call::Config& config,
   call_stats_->RegisterStatsObserver(&receive_side_cc_);
   call_stats_->RegisterStatsObserver(transport_send_->send_side_cc());
 
-  module_process_thread_->Start();
-  module_process_thread_->RegisterModule(call_stats_.get(), RTC_FROM_HERE);
-  module_process_thread_->RegisterModule(&receive_side_cc_, RTC_FROM_HERE);
-  module_process_thread_->RegisterModule(transport_send_->send_side_cc(),
-                                         RTC_FROM_HERE);
+  // We have to attach the pacer to the pacer thread before starting the
+  // module process thread to avoid a race accessing the process thread
+  // both from the process thread and the pacer thread.
   pacer_thread_->RegisterModule(transport_send_->send_side_cc()->pacer(),
                                 RTC_FROM_HERE);
   pacer_thread_->RegisterModule(
       receive_side_cc_.GetRemoteBitrateEstimator(true), RTC_FROM_HERE);
-
   pacer_thread_->Start();
+
+  module_process_thread_->RegisterModule(call_stats_.get(), RTC_FROM_HERE);
+  module_process_thread_->RegisterModule(&receive_side_cc_, RTC_FROM_HERE);
+  module_process_thread_->RegisterModule(transport_send_->send_side_cc(),
+                                         RTC_FROM_HERE);
+  module_process_thread_->Start();
 }
 
 Call::~Call() {