Use RaceChecker instead of ThreadChecker in remote_bitrate_estimator.

BUG=webrtc:7826

Review-Url: https://codereview.webrtc.org/3006173002
Cr-Original-Commit-Position: refs/heads/master@{#19778}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 423227306112c4011a538bf87ae7f2534f39f724

modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.cc

diff --git a/modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.cc b/modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.cc
index 4f799b3..d3dcfca 100644
--- a/modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.cc
+++ b/modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.cc
@@ -94,7 +94,6 @@
         uma_recorded_(false) {
     RTC_DCHECK(observer_);
     LOG(LS_INFO) << "RemoteBitrateEstimatorAbsSendTime: Instantiating.";
-    network_thread_.DetachFromThread();
 }
 
 void RemoteBitrateEstimatorAbsSendTime::ComputeClusters(
@@ -211,7 +210,7 @@
     int64_t arrival_time_ms,
     size_t payload_size,
     const RTPHeader& header) {
-  RTC_DCHECK(network_thread_.CalledOnValidThread());
+  RTC_DCHECK_RUNS_SERIALIZED(&network_race_);
   if (!header.extension.hasAbsoluteSendTime) {
     LOG(LS_WARNING) << "RemoteBitrateEstimatorAbsSendTimeImpl: Incoming packet "
                        "is missing absolute send time extension!";

modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.h

diff --git a/modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.h b/modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.h
index 135e448..cde266f 100644
--- a/modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.h
+++ b/modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.h
@@ -24,8 +24,8 @@
 #include "webrtc/rtc_base/checks.h"
 #include "webrtc/rtc_base/constructormagic.h"
 #include "webrtc/rtc_base/criticalsection.h"
+#include "webrtc/rtc_base/race_checker.h"
 #include "webrtc/rtc_base/rate_statistics.h"
-#include "webrtc/rtc_base/thread_checker.h"
 
 namespace webrtc {
 
@@ -114,7 +114,7 @@
 
   void TimeoutStreams(int64_t now_ms) RTC_EXCLUSIVE_LOCKS_REQUIRED(&crit_);
 
-  rtc::ThreadChecker network_thread_;
+  rtc::RaceChecker network_race_;
   const Clock* const clock_;
   RemoteBitrateObserver* const observer_;
   std::unique_ptr<InterArrival> inter_arrival_;