Implement periodic bandwidth probing in application-limited region.

webrtc/modules/pacing/paced_sender.cc

 /*
  *  Copyright (c) 2012 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 325 matching lines @@
                                       retransmission, packet_counter_++));
 }
 
 int64_t PacedSender::ExpectedQueueTimeMs() const {
   CriticalSectionScoped cs(critsect_.get());
   RTC_DCHECK_GT(pacing_bitrate_kbps_, 0u);
   return static_cast<int64_t>(packets_->SizeInBytes() * 8 /
                               pacing_bitrate_kbps_);
 }
 
-bool PacedSender::InApplicationLimitedRegion() const {
+rtc::Optional<int64_t> PacedSender::GetApplicationLimitedRegionStartTime()
+    const {
   CriticalSectionScoped cs(critsect_.get());
-  return alr_detector_->InApplicationLimitedRegion();
+  return alr_detector_->GetApplicationLimitedRegionStartTime();
 }
 
 size_t PacedSender::QueueSizePackets() const {
   CriticalSectionScoped cs(critsect_.get());
   return packets_->SizeInPackets();
 }
 
 int64_t PacedSender::QueueInMs() const {
   CriticalSectionScoped cs(critsect_.get());
 
@@ skipping 141 matching lines @@
 void PacedSender::UpdateBudgetWithElapsedTime(int64_t delta_time_ms) {
   media_budget_->IncreaseBudget(delta_time_ms);
   padding_budget_->IncreaseBudget(delta_time_ms);
 }
 
 void PacedSender::UpdateBudgetWithBytesSent(size_t bytes_sent) {
   media_budget_->UseBudget(bytes_sent);
   padding_budget_->UseBudget(bytes_sent);
 }
 }  // namespace webrtc