Add retry support to quic_client_interop_test

gfe-relnote: n/a, test-only
PiperOrigin-RevId: 274644470
Change-Id: Ie68fd26ad452d6489d3fffeba88bcb2bf54e475d
diff --git a/quic/tools/quic_client_interop_test_bin.cc b/quic/tools/quic_client_interop_test_bin.cc
index d6a1da2..3bbb5c5 100644
--- a/quic/tools/quic_client_interop_test_bin.cc
+++ b/quic/tools/quic_client_interop_test_bin.cc
@@ -34,7 +34,8 @@
   kConnectionClose,
   // An H3 transaction succeeded.
   kHttp3,
-  // TODO(nharper): Add Retry to list of tested features.
+  // A RETRY packet was successfully processed.
+  kRetry,
 };
 
 char MatrixLetter(Feature f) {
@@ -49,6 +50,8 @@
       return 'C';
     case Feature::kHttp3:
       return '3';
+    case Feature::kRetry:
+      return 'S';
   }
 }
 
@@ -95,6 +98,12 @@
   while (client->WaitForEvents()) {
   }
 
+  QuicConnectionStats client_stats =
+      client->session()->connection()->GetStats();
+  if (client_stats.retry_packet_processed) {
+    features.insert(Feature::kRetry);
+  }
+
   if (!client->connected()) {
     return features;
   }