Improve probing by ignoring small packets which otherwise break the mechanism.

webrtc/modules/pacing/bitrate_prober.cc

Index: webrtc/modules/pacing/bitrate_prober.cc
diff --git a/webrtc/modules/pacing/bitrate_prober.cc b/webrtc/modules/pacing/bitrate_prober.cc
index 1ed6298ff11f6804982d5a3701a02954c6c1054e..bedb892267e05ca3e804db53e5133ea9b9e2be77 100644
--- a/webrtc/modules/pacing/bitrate_prober.cc
+++ b/webrtc/modules/pacing/bitrate_prober.cc
@@ -29,6 +29,8 @@ int ComputeDeltaFromBitrate(size_t packet_size, int bitrate_bps) {
 }
 }  // namespace
 
+const size_t BitrateProber::kMinProbePacketSize = 200;
+
 BitrateProber::BitrateProber()
     : probing_state_(kDisabled),
       packet_size_last_send_(0),
@@ -88,7 +90,8 @@ int BitrateProber::TimeUntilNextProbe(int64_t now_ms) {
   // We will send the first probe packet immediately if no packet has been
   // sent before.
   int time_until_probe_ms = 0;
-  if (packet_size_last_send_ > 0 && probing_state_ == kProbing) {
+  if (packet_size_last_send_ > kMinProbePacketSize &&
+      probing_state_ == kProbing) {
     int next_delta_ms = ComputeDeltaFromBitrate(packet_size_last_send_,
                                                 probe_bitrates_.front());
     time_until_probe_ms = next_delta_ms - elapsed_time_ms;