Rename thread annotation macros to have RTC prefix for syncrhonization primitives.

other macros (e.g. GUARDED_BY) rename postpone to followup CL
since it touches codebase wider

BUG=webrtc:8198

Review-Url: https://codereview.webrtc.org/3004393002
Cr-Commit-Position: refs/heads/master@{#19701}
diff --git a/webrtc/rtc_base/messagequeue.cc b/webrtc/rtc_base/messagequeue.cc
index 883735c..3dd1142 100644
--- a/webrtc/rtc_base/messagequeue.cc
+++ b/webrtc/rtc_base/messagequeue.cc
@@ -23,16 +23,16 @@
 const int kMaxMsgLatency = 150;  // 150 ms
 const int kSlowDispatchLoggingThreshold = 50;  // 50 ms
 
-class SCOPED_LOCKABLE MarkProcessingCritScope {
+class RTC_SCOPED_LOCKABLE MarkProcessingCritScope {
  public:
   MarkProcessingCritScope(const CriticalSection* cs, size_t* processing)
-      EXCLUSIVE_LOCK_FUNCTION(cs)
+      RTC_EXCLUSIVE_LOCK_FUNCTION(cs)
       : cs_(cs), processing_(processing) {
     cs_->Enter();
     *processing_ += 1;
   }
 
-  ~MarkProcessingCritScope() UNLOCK_FUNCTION() {
+  ~MarkProcessingCritScope() RTC_UNLOCK_FUNCTION() {
     *processing_ -= 1;
     cs_->Leave();
   }