Change return type of CongestionController::pacer() method.

webrtc/modules/congestion_controller/include/congestion_controller.h

 /*
  *  Copyright (c) 2012 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 63 matching lines @@
   // Resets both the BWE state and the bitrate estimator. Note the first
   // argument is the bitrate_bps.
   virtual void ResetBweAndBitrates(int bitrate_bps,
                                    int min_bitrate_bps,
                                    int max_bitrate_bps);
   virtual void SignalNetworkState(NetworkState state);
   virtual BitrateController* GetBitrateController() const;
   virtual RemoteBitrateEstimator* GetRemoteBitrateEstimator(
       bool send_side_bwe);
   virtual int64_t GetPacerQueuingDelayMs() const;
-  // TODO(nisse): Delete this accessor function. The pacer should be
-  // internal to the congestion controller.
-  virtual PacedSender* pacer() { return pacer_.get(); }
+  // TODO(nisse): Rename or delete this accessor function. The pacer
+  // should be internal to the congestion controller.
+  virtual RtpPacketSender* pacer() { return pacer_.get(); }
   virtual TransportFeedbackObserver* GetTransportFeedbackObserver();
   RateLimiter* GetRetransmissionRateLimiter();
   void EnablePeriodicAlrProbing(bool enable);
 
   // SetAllocatedSendBitrateLimits sets bitrates limits imposed by send codec
   // settings.
   // |min_send_bitrate_bps| is the total minimum send bitrate required by all
   // sending streams.  This is the minimum bitrate the PacedSender will use.
   // Note that CongestionController::OnNetworkChanged can still be called with
   // a lower bitrate estimate.
@@ skipping 17 matching lines @@
   void MaybeTriggerOnNetworkChanged();
 
   bool IsSendQueueFull() const;
   bool IsNetworkDown() const;
   bool HasNetworkParametersToReportChanged(uint32_t bitrate_bps,
                                            uint8_t fraction_loss,
                                            int64_t rtt);
   Clock* const clock_;
   Observer* const observer_;
   PacketRouter* const packet_router_;
+  // TODO(nisse): Convert to TaskQueue.

[the sun, 2016/12/15 15:11:32]

Yes, please!

+  const std::unique_ptr<ProcessThread> pacer_thread_;
   const std::unique_ptr<PacedSender> pacer_;
   const std::unique_ptr<RemoteBitrateEstimator> remote_bitrate_estimator_;
   const std::unique_ptr<BitrateController> bitrate_controller_;
   const std::unique_ptr<ProbeController> probe_controller_;
   const std::unique_ptr<RateLimiter> retransmission_rate_limiter_;
   RemoteEstimatorProxy remote_estimator_proxy_;
   TransportFeedbackAdapter transport_feedback_adapter_;
   int min_bitrate_bps_;
   int max_bitrate_bps_;
   rtc::CriticalSection critsect_;
   uint32_t last_reported_bitrate_bps_ GUARDED_BY(critsect_);
   uint8_t last_reported_fraction_loss_ GUARDED_BY(critsect_);
   int64_t last_reported_rtt_ GUARDED_BY(critsect_);
   NetworkState network_state_ GUARDED_BY(critsect_);
 
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(CongestionController);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_CONGESTION_CONTROLLER_INCLUDE_CONGESTION_CONTROLLER_H_