Add a timestamp field to QUIC's CachedNetworkParams proto message.

net/tools/quic/quic_server_session.cc

Index: net/tools/quic/quic_server_session.cc
diff --git a/net/tools/quic/quic_server_session.cc b/net/tools/quic/quic_server_session.cc
index 64ac1105072a1a96349838183a599d5aac05052d..e2245ae2f3f0180504f563b02ce79acf05e09f44 100644
--- a/net/tools/quic/quic_server_session.cc
+++ b/net/tools/quic/quic_server_session.cc
@@ -128,6 +128,8 @@ void QuicServerSession::OnCongestionWindowChange(QuicTime now) {
       bandwidth_recorder.EstimateRecordedDuringSlowStart()
           ? CachedNetworkParameters::SLOW_START
           : CachedNetworkParameters::CONGESTION_AVOIDANCE);
+  cached_network_params.set_timestamp(
+      connection()->clock()->WallNow().ToUNIXSeconds());
   if (!serving_region_.empty()) {
     cached_network_params.set_serving_region(serving_region_);
   }