Added protobuf message for loss-based BWE events, and wired it up to the send side bandwidth estima…

webrtc/modules/bitrate_controller/send_side_bandwidth_estimation.cc

Index: webrtc/modules/bitrate_controller/send_side_bandwidth_estimation.cc
diff --git a/webrtc/modules/bitrate_controller/send_side_bandwidth_estimation.cc b/webrtc/modules/bitrate_controller/send_side_bandwidth_estimation.cc
index 9fa7b0dfc051b8f4050e70ba86fcdcf081064e3d..c1c10e8262a496e9c3befbc00624982568a96ba8 100644
--- a/webrtc/modules/bitrate_controller/send_side_bandwidth_estimation.cc
+++ b/webrtc/modules/bitrate_controller/send_side_bandwidth_estimation.cc
@@ -16,6 +16,7 @@
 #include "webrtc/system_wrappers/include/field_trial.h"
 #include "webrtc/system_wrappers/include/logging.h"
 #include "webrtc/system_wrappers/include/metrics.h"
+#include "webrtc/call/rtc_event_log.h"
 
 namespace webrtc {
 namespace {
@@ -59,7 +60,8 @@ SendSideBandwidthEstimation::SendSideBandwidthEstimation()
       initially_lost_packets_(0),
       bitrate_at_2_seconds_kbps_(0),
       uma_update_state_(kNoUpdate),
-      rampup_uma_stats_updated_(kNumUmaRampupMetrics, false) {}
+      rampup_uma_stats_updated_(kNumUmaRampupMetrics, false),
+      event_log_(nullptr) {}
 
 SendSideBandwidthEstimation::~SendSideBandwidthEstimation() {}
 
@@ -206,6 +208,11 @@ void SendSideBandwidthEstimation::UpdateEstimate(int64_t now_ms) {
       // rates).
       bitrate_ += 1000;
 
+      if (event_log_) {
+        event_log_->LogBwePacketLossEvent(
+            bitrate_, last_fraction_loss_,
+            expected_packets_since_last_loss_update_);
+      }
     } else if (last_fraction_loss_ <= 26) {
       // Loss between 2% - 10%: Do nothing.
     } else {
@@ -224,6 +231,11 @@ void SendSideBandwidthEstimation::UpdateEstimate(int64_t now_ms) {
             512.0);
         has_decreased_since_last_fraction_loss_ = true;
       }
+      if (event_log_) {
+        event_log_->LogBwePacketLossEvent(
+            bitrate_, last_fraction_loss_,
+            expected_packets_since_last_loss_update_);
+      }
     }
   }
   bitrate_ = CapBitrateToThresholds(now_ms, bitrate_);
@@ -274,4 +286,9 @@ uint32_t SendSideBandwidthEstimation::CapBitrateToThresholds(
   }
   return bitrate;
 }
+
+void SendSideBandwidthEstimation::SetEventLog(RtcEventLog* event_log) {
+  event_log_ = event_log;
+}
+
 }  // namespace webrtc