Update thread annotiation macros in modules to use RTC_ prefix

webrtc/modules/audio_processing/level_estimator_impl.h

Index: webrtc/modules/audio_processing/level_estimator_impl.h
diff --git a/webrtc/modules/audio_processing/level_estimator_impl.h b/webrtc/modules/audio_processing/level_estimator_impl.h
index db7217493d0eaa530a2bbeeebf8c63b3d0abc3e9..68b193211678409d8e73a92ca2c91b2bc8956821 100644
--- a/webrtc/modules/audio_processing/level_estimator_impl.h
+++ b/webrtc/modules/audio_processing/level_estimator_impl.h
@@ -38,8 +38,8 @@ class LevelEstimatorImpl : public LevelEstimator {
 
  private:
   rtc::CriticalSection* const crit_ = nullptr;
-  bool enabled_ GUARDED_BY(crit_) = false;
-  std::unique_ptr<RmsLevel> rms_ GUARDED_BY(crit_);
+  bool enabled_ RTC_GUARDED_BY(crit_) = false;
+  std::unique_ptr<RmsLevel> rms_ RTC_GUARDED_BY(crit_);
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(LevelEstimatorImpl);
 };
 }  // namespace webrtc