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

webrtc/modules/congestion_controller/delay_based_bwe.h

 /*
  *  Copyright (c) 2016 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 28 matching lines @@
 
   struct Result {
     Result() : updated(false), probe(false), target_bitrate_bps(0) {}
     Result(bool probe, uint32_t target_bitrate_bps)
         : updated(true), probe(probe), target_bitrate_bps(target_bitrate_bps) {}
     bool updated;
     bool probe;
     uint32_t target_bitrate_bps;
   };
 
-  DelayBasedBwe(RtcEventLog* event_log, Clock* clock);
+  DelayBasedBwe(RtcEventLog* event_log, const Clock* clock);
   virtual ~DelayBasedBwe() {}
 
   Result IncomingPacketFeedbackVector(
       const std::vector<PacketFeedback>& packet_feedback_vector);
   void OnRttUpdate(int64_t avg_rtt_ms, int64_t max_rtt_ms);
   bool LatestEstimate(std::vector<uint32_t>* ssrcs,
                       uint32_t* bitrate_bps) const;
   void SetStartBitrate(int start_bitrate_bps);
   void SetMinBitrate(int min_bitrate_bps);
   int64_t GetProbingIntervalMs() const;
@@ skipping 27 matching lines @@
   // estimate exists.
   bool UpdateEstimate(int64_t packet_arrival_time_ms,
                       int64_t now_ms,
                       rtc::Optional<uint32_t> acked_bitrate_bps,
                       uint32_t* target_bitrate_bps);
   const bool in_trendline_experiment_;
   const bool in_median_slope_experiment_;
 
   rtc::ThreadChecker network_thread_;
   RtcEventLog* const event_log_;
-  Clock* const clock_;
+  const Clock* const clock_;
   std::unique_ptr<InterArrival> inter_arrival_;
   std::unique_ptr<OveruseEstimator> kalman_estimator_;
   std::unique_ptr<TrendlineEstimator> trendline_estimator_;
   std::unique_ptr<MedianSlopeEstimator> median_slope_estimator_;
   OveruseDetector detector_;
   BitrateEstimator receiver_incoming_bitrate_;
   int64_t last_update_ms_;
   int64_t last_seen_packet_ms_;
   bool uma_recorded_;
   AimdRateControl rate_control_;
   ProbeBitrateEstimator probe_bitrate_estimator_;
   size_t trendline_window_size_;
   double trendline_smoothing_coeff_;
   double trendline_threshold_gain_;
   ProbingIntervalEstimator probing_interval_estimator_;
   size_t median_slope_window_size_;
   double median_slope_threshold_gain_;
   int consecutive_delayed_feedbacks_;
   uint32_t last_logged_bitrate_;
   BandwidthUsage last_logged_state_;
 
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(DelayBasedBwe);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_CONGESTION_CONTROLLER_DELAY_BASED_BWE_H_