Mark |Clock*| as |const Clock*| (for some CongestionController and BWE related modules)

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 41 matching lines @@
   class Observer {
    public:
     virtual void OnNetworkChanged(uint32_t bitrate_bps,
                                   uint8_t fraction_loss,  // 0 - 255.
                                   int64_t rtt_ms,
                                   int64_t probing_interval_ms) = 0;
 
    protected:
     virtual ~Observer() {}
   };
-  CongestionController(Clock* clock,
+  CongestionController(const Clock* clock,
                        Observer* observer,
                        RemoteBitrateObserver* remote_bitrate_observer,
                        RtcEventLog* event_log,
                        PacketRouter* packet_router);
-  CongestionController(Clock* clock,
+  CongestionController(const Clock* clock,
                        Observer* observer,
                        RemoteBitrateObserver* remote_bitrate_observer,
                        RtcEventLog* event_log,
                        PacketRouter* packet_router,
                        std::unique_ptr<PacedSender> pacer);
   virtual ~CongestionController();
 
   virtual void OnReceivedPacket(int64_t arrival_time_ms,
                                 size_t payload_size,
                                 const RTPHeader& header);
@@ skipping 44 matching lines @@
   // Implements TransportFeedbackObserver.
   void AddPacket(uint16_t sequence_number,
                  size_t length,
                  const PacedPacketInfo& pacing_info) override;
   void OnTransportFeedback(const rtcp::TransportFeedback& feedback) override;
   std::vector<PacketFeedback> GetTransportFeedbackVector() const override;
 
  private:
   class WrappingBitrateEstimator : public RemoteBitrateEstimator {
    public:
-    WrappingBitrateEstimator(RemoteBitrateObserver* observer, Clock* clock);
+    WrappingBitrateEstimator(RemoteBitrateObserver* observer,
+                             const Clock* clock);
 
     virtual ~WrappingBitrateEstimator() {}
 
     void IncomingPacket(int64_t arrival_time_ms,
                         size_t payload_size,
                         const RTPHeader& header) override;
 
     void Process() override;
 
     int64_t TimeUntilNextProcess() override;
 
     void OnRttUpdate(int64_t avg_rtt_ms, int64_t max_rtt_ms) override;
 
     void RemoveStream(unsigned int ssrc) override;
 
     bool LatestEstimate(std::vector<unsigned int>* ssrcs,
                         unsigned int* bitrate_bps) const override;
 
     void SetMinBitrate(int min_bitrate_bps) override;
 
    private:
     void PickEstimatorFromHeader(const RTPHeader& header)
         EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
     void PickEstimator() EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
     RemoteBitrateObserver* observer_;
-    Clock* const clock_;
+    const Clock* const clock_;
     rtc::CriticalSection crit_sect_;
     std::unique_ptr<RemoteBitrateEstimator> rbe_;
     bool using_absolute_send_time_;
     uint32_t packets_since_absolute_send_time_;
     int min_bitrate_bps_;
 
     RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(WrappingBitrateEstimator);
   };
 
   void MaybeTriggerOnNetworkChanged();
 
   bool IsSendQueueFull() const;
   bool IsNetworkDown() const;
   bool HasNetworkParametersToReportChanged(uint32_t bitrate_bps,
                                            uint8_t fraction_loss,
                                            int64_t rtt);
-  Clock* const clock_;
+  const Clock* const clock_;
   Observer* const observer_;
   RtcEventLog* const event_log_;
   PacketRouter* const packet_router_;
   const std::unique_ptr<PacedSender> pacer_;
   const std::unique_ptr<BitrateController> bitrate_controller_;
   const std::unique_ptr<ProbeController> probe_controller_;
   const std::unique_ptr<RateLimiter> retransmission_rate_limiter_;
   WrappingBitrateEstimator remote_bitrate_estimator_;
   RemoteEstimatorProxy remote_estimator_proxy_;
   TransportFeedbackAdapter transport_feedback_adapter_;
   int min_bitrate_bps_;
   int max_bitrate_bps_;
   rtc::CriticalSection network_state_lock_;
   uint32_t last_reported_bitrate_bps_ GUARDED_BY(network_state_lock_);
   uint8_t last_reported_fraction_loss_ GUARDED_BY(network_state_lock_);
   int64_t last_reported_rtt_ GUARDED_BY(network_state_lock_);
   NetworkState network_state_ GUARDED_BY(network_state_lock_);
   rtc::CriticalSection bwe_lock_;
   std::unique_ptr<DelayBasedBwe> delay_based_bwe_ GUARDED_BY(bwe_lock_);
 
   rtc::ThreadChecker worker_thread_checker_;
 
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(CongestionController);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_CONGESTION_CONTROLLER_INCLUDE_CONGESTION_CONTROLLER_H_