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

webrtc/modules/congestion_controller/probe_controller.cc

 /*
  *  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 29 matching lines @@
 constexpr int64_t kAlrPeriodicProbingIntervalMs = 5000;
 
 // Minimum probe bitrate percentage to probe further for repeated probes,
 // relative to the previous probe. For example, if 1Mbps probe results in
 // 80kbps, then we'll probe again at 1.6Mbps. In that case second probe won't be
 // sent if we get 600kbps from the first one.
 constexpr int kRepeatedProbeMinPercentage = 70;
 
 }  // namespace
 
-ProbeController::ProbeController(PacedSender* pacer, Clock* clock)
+ProbeController::ProbeController(PacedSender* pacer, const Clock* clock)
     : pacer_(pacer), clock_(clock), enable_periodic_alr_probing_(false) {
   Reset();
 }
 
 void ProbeController::SetBitrates(int64_t min_bitrate_bps,
                                   int64_t start_bitrate_bps,
                                   int64_t max_bitrate_bps) {
   rtc::CritScope cs(&critsect_);
 
   if (start_bitrate_bps > 0)  {
@@ skipping 179 matching lines @@
     state_ = State::kWaitingForProbingResult;
     min_bitrate_to_probe_further_bps_ =
         (*(bitrates_to_probe.end() - 1)) * kRepeatedProbeMinPercentage / 100;
   } else {
     state_ = State::kProbingComplete;
     min_bitrate_to_probe_further_bps_ = kExponentialProbingDisabled;
   }
 }
 
 }  // namespace webrtc