Add ability to return moved value from FunctorMessageHandler, Optional.

webrtc/base/thread.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 150 matching lines @@
   // Uses Send() internally, which blocks the current thread until execution
   // is complete.
   // Ex: bool result = thread.Invoke<bool>(RTC_FROM_HERE,
   // &MyFunctionReturningBool);
   // NOTE: This function can only be called when synchronous calls are allowed.
   // See ScopedDisallowBlockingCalls for details.
   template <class ReturnT, class FunctorT>
   ReturnT Invoke(const Location& posted_from, const FunctorT& functor) {
     FunctorMessageHandler<ReturnT, FunctorT> handler(functor);
     InvokeInternal(posted_from, &handler);
-    return handler.result();
+    return handler.MoveResult();
   }
 
   // From MessageQueue
   void Clear(MessageHandler* phandler,
              uint32_t id = MQID_ANY,
              MessageList* removed = NULL) override;
   void ReceiveSends() override;
 
   // ProcessMessages will process I/O and dispatch messages until:
   //  1) cms milliseconds have elapsed (returns true)
@@ skipping 147 matching lines @@
 
  private:
   SocketServer* old_ss_;
 
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(SocketServerScope);
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_THREAD_H_