ProbingEstimator: Erase history based on time threshold

webrtc/modules/congestion_controller/probe_bitrate_estimator.h

Index: webrtc/modules/congestion_controller/probe_bitrate_estimator.h
diff --git a/webrtc/modules/congestion_controller/probe_bitrate_estimator.h b/webrtc/modules/congestion_controller/probe_bitrate_estimator.h
index 7f0c4569c97f039976e822d94887987d66e8e994..3298106b557079ba4c72f9bddb26bb825272856f 100644
--- a/webrtc/modules/congestion_controller/probe_bitrate_estimator.h
+++ b/webrtc/modules/congestion_controller/probe_bitrate_estimator.h
@@ -18,25 +18,16 @@
 
 namespace webrtc {
 
-struct ProbingResult {
-  static constexpr int kNoEstimate = -1;
-
-  ProbingResult();
-  ProbingResult(int bps, int64_t timestamp);
-  bool valid() const;
-
-  int bps;
-  int64_t timestamp;
-};
-
 class ProbeBitrateEstimator {
  public:
   ProbeBitrateEstimator();
 
-  // Should be called for every packet we receive feedback about. If the
-  // packet was used for probing it will validate/calculate the resulting
-  // bitrate and return the result.
-  ProbingResult PacketFeedback(const PacketInfo& packet_info);
+  // Should be called for every probe packet we receive feedback about.
+  // Estimates highest bitrate across all probe clusters received.
+  // |min_probe_clusters| specifies minimum number of probe clusters to
+  // have a valid BW value.
+  int HandleProbeAndEstimateBitrate(const PacketInfo& packet_info,

[danilchap, 2016/08/19 11:46:30]

this function returns -1 when bitrate doesn't change and
the bitrate when it may be changed (when it is recalculated, probably to the
same cluster).

May it would be cleaner if the funciton always return highest (cached) bitrate,
even if is obviously same as before.
Or return bool to indicate the bitrate may be changed and have an output
parameter or accessor to get highest bitrate so far.

[Irfan, 2016/08/22 18:11:17]

Given that I have removed the highest across clusters functionality now, I think
this is pretty clean now in that it returns bitrate for the cluster to which the
probe belongs to.

+                                    int min_probe_clusters);
 
  private:
   struct AggregatedCluster {
@@ -46,10 +37,16 @@ class ProbeBitrateEstimator {
     int64_t first_receive_ms = std::numeric_limits<int64_t>::max();
     int64_t last_receive_ms = 0;
     size_t size = 0;
+    int bps = 0;
   };
 
+  // Erases old cluster data that was seen before |timestamp_ms|.
+  void EraseOldClusters(int64_t timestamp_ms);
+
+  int HighestBitrateOnClusters();
+
   std::map<int, AggregatedCluster> clusters_;
-  int last_valid_cluster_id_;
+  int valid_clusters_ = 0;
 };
 
 }  // namespace webrtc