Update thread annotiation macros to use RTC_ prefix

webrtc/audio/audio_state.h

Index: webrtc/audio/audio_state.h
diff --git a/webrtc/audio/audio_state.h b/webrtc/audio/audio_state.h
index c8ce44b8b2ed18c680547effce90ae8f4e1ea44e..893c1f9406b72204f72468f10aeea37d5627639e 100644
--- a/webrtc/audio/audio_state.h
+++ b/webrtc/audio/audio_state.h
@@ -55,7 +55,7 @@ class AudioState final : public webrtc::AudioState,
   // The critical section isn't strictly needed in this case, but xSAN bots may
   // trigger on unprotected cross-thread access.
   rtc::CriticalSection crit_sect_;
-  bool typing_noise_detected_ GUARDED_BY(crit_sect_) = false;
+  bool typing_noise_detected_ RTC_GUARDED_BY(crit_sect_) = false;
 
   // Reference count; implementation copied from rtc::RefCountedObject.
   mutable volatile int ref_count_ = 0;