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

webrtc/modules/remote_bitrate_estimator/send_time_history.cc

 /*
  *  Copyright (c) 2015 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.
  */
 
 #include "webrtc/modules/remote_bitrate_estimator/include/send_time_history.h"
 
 #include "webrtc/base/checks.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
 #include "webrtc/system_wrappers/include/clock.h"
 
 namespace webrtc {
 
-SendTimeHistory::SendTimeHistory(Clock* clock, int64_t packet_age_limit_ms)
+SendTimeHistory::SendTimeHistory(const Clock* clock,
+                                 int64_t packet_age_limit_ms)
     : clock_(clock), packet_age_limit_ms_(packet_age_limit_ms) {}
 
 SendTimeHistory::~SendTimeHistory() {}
 
 void SendTimeHistory::Clear() {
   history_.clear();
 }
 
 void SendTimeHistory::AddAndRemoveOld(uint16_t sequence_number,
                                       size_t payload_size,
@@ skipping 41 matching lines @@
   int64_t arrival_time_ms = packet_feedback->arrival_time_ms;
   *packet_feedback = it->second;
   packet_feedback->arrival_time_ms = arrival_time_ms;
 
   if (remove)
     history_.erase(it);
   return true;
 }
 
 }  // namespace webrtc