Implement periodic bandwidth probing in application-limited region.

webrtc/modules/congestion_controller/probe_controller.h

 /*
  *  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.
  */
 
@@ skipping 18 matching lines @@
   ProbeController(PacedSender* pacer, Clock* clock);
 
   void SetBitrates(int min_bitrate_bps,
                    int start_bitrate_bps,
                    int max_bitrate_bps);
 
   void OnNetworkStateChanged(NetworkState state);
 
   void SetEstimatedBitrate(int bitrate_bps);
 
+  void EnablePeriodicAlrProbing(bool enable);
+  void Process();
+
  private:
   enum class State {
     // Initial state where no probing has been triggered yet.
     kInit,
     // Waiting for probing results to continue further probing.
     kWaitingForProbingResult,
     // Probing is complete.
     kProbingComplete,
   };
 
   void InitiateExponentialProbing() EXCLUSIVE_LOCKS_REQUIRED(critsect_);
-  void InitiateProbing(std::initializer_list<int> bitrates_to_probe,
+  void InitiateProbing(int64_t now_ms,
+                       std::initializer_list<int> bitrates_to_probe,
                        int min_bitrate_to_probe_further_bps)
       EXCLUSIVE_LOCKS_REQUIRED(critsect_);
 
   rtc::CriticalSection critsect_;
   PacedSender* const pacer_;
   Clock* const clock_;
   NetworkState network_state_ GUARDED_BY(critsect_);
   State state_ GUARDED_BY(critsect_);
   int min_bitrate_to_probe_further_bps_ GUARDED_BY(critsect_);
   int64_t time_last_probing_initiated_ms_ GUARDED_BY(critsect_);
   int estimated_bitrate_bps_ GUARDED_BY(critsect_);
   int start_bitrate_bps_ GUARDED_BY(critsect_);
   int max_bitrate_bps_ GUARDED_BY(critsect_);
   int64_t last_alr_probing_time_ GUARDED_BY(critsect_);
+  bool enable_periodic_alr_probing_ GUARDED_BY(critsect_);
 
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(ProbeController);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_CONGESTION_CONTROLLER_PROBE_CONTROLLER_H_