Fixing potential AsyncInvoker deadlock that occurs for "reentrant" invocations.

webrtc/base/asyncinvoker.h

 /*
  *  Copyright 2014 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 102 matching lines @@
                 Thread* thread,
                 std::unique_ptr<AsyncClosure> closure,
                 uint32_t id);
   void DoInvokeDelayed(const Location& posted_from,
                        Thread* thread,
                        std::unique_ptr<AsyncClosure> closure,
                        uint32_t delay_ms,
                        uint32_t id);
   volatile int pending_invocations_ = 0;
   Event invocation_complete_;
-  bool destroying_ = false;
+  int destroying_ = 0;
   friend class AsyncClosure;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(AsyncInvoker);
 };
 
 // Similar to AsyncInvoker, but guards against the Thread being destroyed while
 // there are outstanding dangling pointers to it. It will connect to the current
 // thread in the constructor, and will get notified when that thread is
 // destroyed. After GuardedAsyncInvoker is constructed, it can be used from
 // other threads to post functors to the thread it was constructed on. If that
@@ skipping 78 matching lines @@
   void ThreadDestroyed();
 
   CriticalSection crit_;
   Thread* thread_ GUARDED_BY(crit_);
   AsyncInvoker invoker_ GUARDED_BY(crit_);
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_ASYNCINVOKER_H_