Handle initialization race in TaskQueue on Windows, discovered by drmemory

webrtc/base/task_queue.h

 /*
  *  Copyright 2016 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.
  */
 
 #ifndef WEBRTC_BASE_TASK_QUEUE_H_
 #define WEBRTC_BASE_TASK_QUEUE_H_
 
 #include <list>
 #include <memory>
+#include <unordered_map>
 
 #if defined(WEBRTC_MAC) && !defined(WEBRTC_BUILD_LIBEVENT)
 #include <dispatch/dispatch.h>
 #endif
 
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/base/criticalsection.h"
 
 #if defined(WEBRTC_WIN) || defined(WEBRTC_BUILD_LIBEVENT)
 #include "webrtc/base/platform_thread.h"
@@ skipping 220 matching lines @@
   rtc::CriticalSection pending_lock_;
   std::list<std::unique_ptr<QueuedTask>> pending_ GUARDED_BY(pending_lock_);
   std::list<PostAndReplyTask*> pending_replies_ GUARDED_BY(pending_lock_);
 #elif defined(WEBRTC_MAC)
   struct QueueContext;
   struct TaskContext;
   struct PostTaskAndReplyContext;
   dispatch_queue_t queue_;
   QueueContext* const context_;
 #elif defined(WEBRTC_WIN)
+  typedef std::unordered_map<UINT_PTR, std::unique_ptr<QueuedTask>>
+      DelayedTasks;
   static bool ThreadMain(void* context);
+  static bool ProcessQueuedMessages(DelayedTasks* delayed_tasks);
 
   class WorkerThread : public PlatformThread {
    public:
     WorkerThread(ThreadRunFunction func, void* obj, const char* thread_name)
         : PlatformThread(func, obj, thread_name) {}
 
     bool QueueAPC(PAPCFUNC apc_function, ULONG_PTR data) {
       return PlatformThread::QueueAPC(apc_function, data);
     }
   };
   WorkerThread thread_;
 #else
 #error not supported.
 #endif
 
   RTC_DISALLOW_COPY_AND_ASSIGN(TaskQueue);
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_TASK_QUEUE_H_