Audit of kConstants missing the const qualifier

webrtc/modules/audio_processing/level_controller/noise_spectrum_estimator.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.
  */
 
 #include "webrtc/modules/audio_processing/level_controller/noise_spectrum_estimator.h"
 
 #include <string.h>
 #include <algorithm>
 
 #include "webrtc/modules/audio_processing/logging/apm_data_dumper.h"
 #include "webrtc/rtc_base/array_view.h"
 #include "webrtc/rtc_base/arraysize.h"
 
 namespace webrtc {
 namespace {
-float kMinNoisePower = 100.f;
+constexpr float kMinNoisePower = 100.f;
 }  // namespace
 
 NoiseSpectrumEstimator::NoiseSpectrumEstimator(ApmDataDumper* data_dumper)
     : data_dumper_(data_dumper) {
   Initialize();
 }
 
 void NoiseSpectrumEstimator::Initialize() {
   std::fill(noise_spectrum_, noise_spectrum_ + arraysize(noise_spectrum_),
             kMinNoisePower);
@@ skipping 26 matching lines @@
   // Ensure that the noise spectal estimate does not become too low.
   for (auto& v : noise_spectrum_) {
     v = std::max(v, kMinNoisePower);
   }
 
   data_dumper_->DumpRaw("lc_noise_spectrum", 65, noise_spectrum_);
   data_dumper_->DumpRaw("lc_signal_spectrum", spectrum);
 }
 
 }  // namespace webrtc