Implement periodic bandwidth probing in application-limited region.

webrtc/media/engine/webrtcvideoengine2.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 1074 matching lines @@
   rtc::CritScope stream_lock(&stream_crit_);
 
   if (!ValidateSendSsrcAvailability(sp))
     return false;
 
   for (uint32_t used_ssrc : sp.ssrcs)
     send_ssrcs_.insert(used_ssrc);
 
   webrtc::VideoSendStream::Config config(this);
   config.suspend_below_min_bitrate = video_config_.suspend_below_min_bitrate;
+  config.periodic_alr_bandwidth_probing =
+      video_config_.periodic_alr_bandwidth_probing;
   WebRtcVideoSendStream* stream = new WebRtcVideoSendStream(
       call_, sp, std::move(config), default_send_options_,
       external_encoder_factory_, video_config_.enable_cpu_overuse_detection,
       bitrate_config_.max_bitrate_bps, send_codec_, send_rtp_extensions_,
       send_params_);
 
   uint32_t ssrc = sp.first_ssrc();
   RTC_DCHECK(ssrc != 0);
   send_streams_[ssrc] = stream;
 
@@ skipping 1443 matching lines @@
         rtx_mapping[video_codecs[i].codec.id] !=
             ulpfec_config.red_payload_type) {
       video_codecs[i].rtx_payload_type = rtx_mapping[video_codecs[i].codec.id];
     }
   }
 
   return video_codecs;
 }
 
 }  // namespace cricket