Replace reentrant check to be more explicit and avoid a data race when comparing

webrtc/base/messagequeue.h

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 50 matching lines @@
   MessageQueueManager();
   ~MessageQueueManager();
 
   void AddInternal(MessageQueue *message_queue);
   void RemoveInternal(MessageQueue *message_queue);
   void ClearInternal(MessageHandler *handler);
   void ProcessAllMessageQueuesInternal();
 
   static MessageQueueManager* instance_;
   // This list contains all live MessageQueues.
-  std::vector<MessageQueue *> message_queues_;
+  std::vector<MessageQueue*> message_queues_ GUARDED_BY(crit_);
+
+  // Acquire this with DebugNonReentrantCritScope.
   CriticalSection crit_;
+  bool locked_ GUARDED_BY(crit_);
 };
 
 // Derive from this for specialized data
 // App manages lifetime, except when messages are purged
 
 class MessageData {
  public:
   MessageData() {}
   virtual ~MessageData() {}
 };
@@ skipping 218 matching lines @@
   // Used if SocketServer ownership lies with |this|.
   std::unique_ptr<SocketServer> own_ss_;
   SharedExclusiveLock ss_lock_;
 
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(MessageQueue);
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_MESSAGEQUEUE_H_