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

webrtc/modules/congestion_controller/probe_controller.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.
  */
 
 #ifndef WEBRTC_MODULES_CONGESTION_CONTROLLER_PROBE_CONTROLLER_H_
 #define WEBRTC_MODULES_CONGESTION_CONTROLLER_PROBE_CONTROLLER_H_
 
 #include <initializer_list>
 
 #include "webrtc/base/criticalsection.h"
 #include "webrtc/common_types.h"
 #include "webrtc/modules/pacing/paced_sender.h"
 
 namespace webrtc {
 
 class Clock;
 
 // This class controls initiation of probing to estimate initial channel
 // capacity. There is also support for probing during a session when max
 // bitrate is adjusted by an application.
 class ProbeController {
  public:
-  ProbeController(PacedSender* pacer, Clock* clock);
+  ProbeController(PacedSender* pacer, const Clock* clock);
 
   void SetBitrates(int64_t min_bitrate_bps,
                    int64_t start_bitrate_bps,
                    int64_t max_bitrate_bps);
 
   void OnNetworkStateChanged(NetworkState state);
 
   void SetEstimatedBitrate(int64_t bitrate_bps);
 
   void EnablePeriodicAlrProbing(bool enable);
@@ skipping 14 matching lines @@
     kProbingComplete,
   };
 
   void InitiateExponentialProbing() EXCLUSIVE_LOCKS_REQUIRED(critsect_);
   void InitiateProbing(int64_t now_ms,
                        std::initializer_list<int64_t> bitrates_to_probe,
                        bool probe_further) EXCLUSIVE_LOCKS_REQUIRED(critsect_);
 
   rtc::CriticalSection critsect_;
   PacedSender* const pacer_;
-  Clock* const clock_;
+  const Clock* const clock_;
   NetworkState network_state_ GUARDED_BY(critsect_);
   State state_ GUARDED_BY(critsect_);
   int64_t min_bitrate_to_probe_further_bps_ GUARDED_BY(critsect_);
   int64_t time_last_probing_initiated_ms_ GUARDED_BY(critsect_);
   int64_t estimated_bitrate_bps_ GUARDED_BY(critsect_);
   int64_t start_bitrate_bps_ GUARDED_BY(critsect_);
   int64_t max_bitrate_bps_ GUARDED_BY(critsect_);
   int64_t last_alr_probing_time_ GUARDED_BY(critsect_);
   bool enable_periodic_alr_probing_ GUARDED_BY(critsect_);
 
   // For WebRTC.BWE.MidCallProbing.* metric.
   bool mid_call_probing_waiting_for_result_ GUARDED_BY(&critsect_);
   int64_t mid_call_probing_bitrate_bps_ GUARDED_BY(&critsect_);
   int64_t mid_call_probing_succcess_threshold_ GUARDED_BY(&critsect_);
 
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(ProbeController);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_CONGESTION_CONTROLLER_PROBE_CONTROLLER_H_