Update thread annotiation macros to use RTC_ prefix

webrtc/media/base/videoadapter.h

Index: webrtc/media/base/videoadapter.h
diff --git a/webrtc/media/base/videoadapter.h b/webrtc/media/base/videoadapter.h
index 61de4b5980032e4a7603d2353628e4ac1932d831..aa786af0bca0d9fab2b45d261d77261652608fe1 100644
--- a/webrtc/media/base/videoadapter.h
+++ b/webrtc/media/base/videoadapter.h
@@ -75,15 +75,17 @@ class VideoAdapter {
   // Resolution must be divisible by this factor.
   const int required_resolution_alignment_;
   // The target timestamp for the next frame based on requested format.
-  rtc::Optional<int64_t> next_frame_timestamp_ns_ GUARDED_BY(critical_section_);
+  rtc::Optional<int64_t> next_frame_timestamp_ns_
+      RTC_GUARDED_BY(critical_section_);
 
   // Max number of pixels requested via calls to OnOutputFormatRequest,
   // OnResolutionRequest respectively.
   // The adapted output format is the minimum of these.
-  rtc::Optional<VideoFormat> requested_format_ GUARDED_BY(critical_section_);
-  int resolution_request_target_pixel_count_ GUARDED_BY(critical_section_);
-  int resolution_request_max_pixel_count_ GUARDED_BY(critical_section_);
-  int max_framerate_request_ GUARDED_BY(critical_section_);
+  rtc::Optional<VideoFormat> requested_format_
+      RTC_GUARDED_BY(critical_section_);
+  int resolution_request_target_pixel_count_ RTC_GUARDED_BY(critical_section_);
+  int resolution_request_max_pixel_count_ RTC_GUARDED_BY(critical_section_);
+  int max_framerate_request_ RTC_GUARDED_BY(critical_section_);
 
   // The critical section to protect the above variables.
   rtc::CriticalSection critical_section_;