Rewrite of sigslot that avoids vtables.

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 151 matching lines @@
 
 // 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
 // thread dies, any further calls to AsyncInvoke() will be safely ignored.
 class GuardedAsyncInvoker : public sigslot::has_slots<> {
  public:
   GuardedAsyncInvoker();
-  ~GuardedAsyncInvoker() override;
+  ~GuardedAsyncInvoker();
 
   // Synchronously execute all outstanding calls we own, and wait for calls to
   // complete before returning. Optionally filter by message id. The destructor
   // will not wait for outstanding calls, so if that behavior is desired, call
   // Flush() first. Returns false if the thread has died.
   bool Flush(uint32_t id = MQID_ANY);
 
   // Call |functor| asynchronously with no callback upon completion. Returns
   // immediately. Returns false if the thread has died.
   template <class ReturnT, class FunctorT>
@@ skipping 63 matching lines @@
   void ThreadDestroyed();
 
   CriticalSection crit_;
   Thread* thread_ GUARDED_BY(crit_);
   AsyncInvoker invoker_ GUARDED_BY(crit_);
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_ASYNCINVOKER_H_