Bitrate prober and paced sender improvements

webrtc/modules/pacing/bitrate_prober.h

 /*
  *  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 37 matching lines @@
 
   // Returns the number of bytes that the prober recommends for the next probe
   // packet.
   size_t RecommendedPacketSize() const;
 
   // Called to report to the prober that a packet has been sent, which helps the
   // prober know when to move to the next packet in a probe.
   void PacketSent(int64_t now_ms, size_t packet_size);
 
  private:
-  enum ProbingState { kDisabled, kAllowedToProbe, kProbing, kWait };
+  // Resets the state of the prober and clears any cluster/timing data tracked.
+  void ResetState();
+  enum class ProbingState {
+    // Probing will not be triggered in this state at all times.
+    kDisabled,
+    // Probing is enabled and ready to trigger on the first packet arrival.
+    kInactive,
+    // Probe cluster is filled with the set of data rates to be probed and
+    // probes are being sent.
+    kActive,
+    // Probing is enabled, but currently suspended until an explicit trigger
+    // to start probing again.
+    kSuspended,
+  };
 
   struct ProbeCluster {
     int max_probe_packets = 0;
     int sent_probe_packets = 0;
     int probe_bitrate_bps = 0;
     int id = -1;
   };
 
   ProbingState probing_state_;
   // Probe bitrate per packet. These are used to compute the delta relative to
   // the previous probe packet based on the size and time when that packet was
   // sent.
   std::queue<ProbeCluster> clusters_;
-  size_t packet_size_last_send_;
-  int64_t time_last_send_ms_;
+  size_t packet_size_last_sent_;
+  // The last time a probe was sent.
+  int64_t time_last_probe_sent_ms_;
   int next_cluster_id_;
 };
 }  // namespace webrtc
 #endif  // WEBRTC_MODULES_PACING_BITRATE_PROBER_H_