Update RateStatistics to handle too-little-data case.

webrtc/modules/remote_bitrate_estimator/aimd_rate_control.cc

 /*
  *  Copyright (c) 2014 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 19 matching lines @@
 AimdRateControl::AimdRateControl()
     : min_configured_bitrate_bps_(
           RemoteBitrateEstimator::kDefaultMinBitrateBps),
       max_configured_bitrate_bps_(30000000),
       current_bitrate_bps_(max_configured_bitrate_bps_),
       avg_max_bitrate_kbps_(-1.0f),
       var_max_bitrate_kbps_(0.4f),
       rate_control_state_(kRcHold),
       rate_control_region_(kRcMaxUnknown),
       time_last_bitrate_change_(-1),
-      current_input_(kBwNormal, 0, 1.0),
+      current_input_(kBwNormal, rtc::Optional<uint32_t>(), 1.0),
       updated_(false),
       time_first_incoming_estimate_(-1),
       bitrate_is_initialized_(false),
       beta_(0.85f),
       rtt_(kDefaultRttMs),
       time_of_last_log_(-1),
       in_experiment_(!AdaptiveThresholdExperimentIsDisabled()) {}
 
 void AimdRateControl::SetMinBitrate(int min_bitrate_bps) {
   min_configured_bitrate_bps_ = min_bitrate_bps;
@@ skipping 29 matching lines @@
     return bitrate_difference > threshold;
   }
   return false;
 }
 
 uint32_t AimdRateControl::LatestEstimate() const {
   return current_bitrate_bps_;
 }
 
 uint32_t AimdRateControl::UpdateBandwidthEstimate(int64_t now_ms) {
-  current_bitrate_bps_ = ChangeBitrate(current_bitrate_bps_,
-                                       current_input_.incoming_bitrate, now_ms);
+  current_bitrate_bps_ = ChangeBitrate(
+      current_bitrate_bps_,
+      current_input_.incoming_bitrate.value_or(current_bitrate_bps_), now_ms);
   if (now_ms - time_of_last_log_ > kLogIntervalMs) {
     time_of_last_log_ = now_ms;
   }
   return current_bitrate_bps_;
 }
 
 void AimdRateControl::SetRtt(int64_t rtt) {
   rtt_ = rtt;
 }
 
 void AimdRateControl::Update(const RateControlInput* input, int64_t now_ms) {
-  assert(input);
+  RTC_CHECK(input);
 
   // Set the initial bit rate value to what we're receiving the first half
   // second.
   if (!bitrate_is_initialized_) {
     const int64_t kInitializationTimeMs = 5000;
     RTC_DCHECK_LE(kBitrateWindowMs, kInitializationTimeMs);
     if (time_first_incoming_estimate_ < 0) {
-      if (input->incoming_bitrate > 0) {
+      if (input->incoming_bitrate)
         time_first_incoming_estimate_ = now_ms;
-      }
     } else if (now_ms - time_first_incoming_estimate_ > kInitializationTimeMs &&
-               input->incoming_bitrate > 0) {
-      current_bitrate_bps_ = input->incoming_bitrate;
+               input->incoming_bitrate) {
+      current_bitrate_bps_ = *input->incoming_bitrate;
       bitrate_is_initialized_ = true;
     }
   }
 
   if (updated_ && current_input_.bw_state == kBwOverusing) {
     // Only update delay factor and incoming bit rate. We always want to react
     // on an over-use.
     current_input_.noise_var = input->noise_var;
     current_input_.incoming_bitrate = input->incoming_bitrate;
   } else {
@@ skipping 177 matching lines @@
 }
 
 void AimdRateControl::ChangeRegion(RateControlRegion region) {
   rate_control_region_ = region;
 }
 
 void AimdRateControl::ChangeState(RateControlState new_state) {
   rate_control_state_ = new_state;
 }
 }  // namespace webrtc