Improve computational performance of BWE by switching list to deque.

webrtc/modules/remote_bitrate_estimator/overuse_estimator.cc

 /*
  *  Copyright (c) 2013 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 111 matching lines @@
   BWE_TEST_LOGGING_PLOT(1, "km", now_ms, K[1]);
   BWE_TEST_LOGGING_PLOT(1, "slope_1/bps", now_ms, slope_);
   BWE_TEST_LOGGING_PLOT(1, "var_noise", now_ms, var_noise_);
 }
 
 double OveruseEstimator::UpdateMinFramePeriod(double ts_delta) {
   double min_frame_period = ts_delta;
   if (ts_delta_hist_.size() >= kMinFramePeriodHistoryLength) {
     ts_delta_hist_.pop_front();
   }
-  std::list<double>::iterator it = ts_delta_hist_.begin();
-  for (; it != ts_delta_hist_.end(); it++) {
-    min_frame_period = std::min(*it, min_frame_period);
+  for (const double old_ts_delta : ts_delta_hist_) {
+    min_frame_period = std::min(old_ts_delta, min_frame_period);
   }
   ts_delta_hist_.push_back(ts_delta);
   return min_frame_period;
 }
 
 void OveruseEstimator::UpdateNoiseEstimate(double residual,
                                            double ts_delta,
                                            bool stable_state) {
   if (!stable_state) {
     return;
@@ skipping 10 matching lines @@
   const double beta = pow(1 - alpha, ts_delta * 30.0 / 1000.0);
   avg_noise_ = beta * avg_noise_
               + (1 - beta) * residual;
   var_noise_ = beta * var_noise_
               + (1 - beta) * (avg_noise_ - residual) * (avg_noise_ - residual);
   if (var_noise_ < 1) {
     var_noise_ = 1;
   }
 }
 }  // namespace webrtc