Log handshake completion time in quic_connection_stats. Logging only.

PiperOrigin-RevId: 327442793
Change-Id: I7fbacca9e8231178e004032b48c3f935e903cc56
diff --git a/quic/core/quic_connection_stats.h b/quic/core/quic_connection_stats.h
index a751f74..5a568e1 100644
--- a/quic/core/quic_connection_stats.h
+++ b/quic/core/quic_connection_stats.h
@@ -129,6 +129,9 @@
   // Creation time, as reported by the QuicClock.
   QuicTime connection_creation_time = QuicTime::Zero();
 
+  // Handshake completion time.
+  QuicTime handshake_completion_time = QuicTime::Zero();
+
   uint64_t blocked_frames_received = 0;
   uint64_t blocked_frames_sent = 0;