Revert of Rename thread annotation macros to have RTC prefix for syncrhonization primitives. (patchset #1 id:1 of https://codereview.webrtc.org/3004393002/ )

Reason for revert:
Breaks chromium bots

Original issue's description:
> 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}
> Committed: https://chromium.googlesource.com/external/webrtc/+/9a2d2dd973ea33ba551db09257441c7f6943bfe4

TBR=kwiberg@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:8198

Review-Url: https://codereview.webrtc.org/3008193002
Cr-Commit-Position: refs/heads/master@{#19702}
diff --git a/webrtc/rtc_base/messagequeue.cc b/webrtc/rtc_base/messagequeue.cc
index 3dd1142..883735c 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 RTC_SCOPED_LOCKABLE MarkProcessingCritScope {
+class SCOPED_LOCKABLE MarkProcessingCritScope {
  public:
   MarkProcessingCritScope(const CriticalSection* cs, size_t* processing)
-      RTC_EXCLUSIVE_LOCK_FUNCTION(cs)
+      EXCLUSIVE_LOCK_FUNCTION(cs)
       : cs_(cs), processing_(processing) {
     cs_->Enter();
     *processing_ += 1;
   }
 
-  ~MarkProcessingCritScope() RTC_UNLOCK_FUNCTION() {
+  ~MarkProcessingCritScope() UNLOCK_FUNCTION() {
     *processing_ -= 1;
     cs_->Leave();
   }