relnote: Use event_time instead of ApproximateNow() in QUIC cubic code. Protected by --quic_use_eve…

net/quic/core/congestion_control/cubic_bytes.cc

Index: net/quic/core/congestion_control/cubic_bytes.cc
diff --git a/net/quic/core/congestion_control/cubic_bytes.cc b/net/quic/core/congestion_control/cubic_bytes.cc
index 388dd008b2c4365bd0690d31aa6f869281ec5360..89ea5e9eaa1c028c926a437094da59b563701922 100644
--- a/net/quic/core/congestion_control/cubic_bytes.cc
+++ b/net/quic/core/congestion_control/cubic_bytes.cc
@@ -117,9 +117,12 @@ QuicByteCount CubicBytes::CongestionWindowAfterPacketLoss(
 QuicByteCount CubicBytes::CongestionWindowAfterAck(
     QuicByteCount acked_bytes,
     QuicByteCount current_congestion_window,
-    QuicTime::Delta delay_min) {
+    QuicTime::Delta delay_min,
+    QuicTime event_time) {
   acked_bytes_count_ += acked_bytes;
-  QuicTime current_time = clock_->ApproximateNow();
+  QuicTime current_time = FLAGS_quic_use_event_time
+                              ? event_time
+                              : clock_->ApproximateNow();
 
   // Cubic is "independent" of RTT, the update is limited by the time elapsed.
   if (last_congestion_window_ == current_congestion_window &&