Deprecate quic_drop_invalid_small_initial_connection_id

gfe-relnote: deprecate gfe2_reloadable_flag_quic_drop_invalid_small_initial_connection_id
PiperOrigin-RevId: 267681921
Change-Id: Ic97992c94c41f3ece887ea8fdc627f48f92457b5

quic/core/quic_dispatcher.cc

diff --git a/quic/core/quic_dispatcher.cc b/quic/core/quic_dispatcher.cc
index 75524aa..542d205 100644
--- a/quic/core/quic_dispatcher.cc
+++ b/quic/core/quic_dispatcher.cc
@@ -348,28 +348,8 @@
     QUIC_DLOG(INFO) << "Packet with short destination connection ID "
                     << server_connection_id << " expected "
                     << static_cast<int>(expected_server_connection_id_length_);
-    if (!GetQuicReloadableFlag(quic_drop_invalid_small_initial_connection_id)) {
-      // Add this connection_id to the time-wait state, to safely reject
-      // future packets.
-      QUIC_DLOG(INFO) << "Adding connection ID " << server_connection_id
-                      << " to time-wait list.";
-      StatelesslyTerminateConnection(
-          server_connection_id, packet_info.form, packet_info.version_flag,
-          packet_info.use_length_prefix, packet_info.version,
-          QUIC_HANDSHAKE_FAILED, "Reject connection",
-          quic::QuicTimeWaitListManager::SEND_STATELESS_RESET);
-
-      DCHECK(time_wait_list_manager_->IsConnectionIdInTimeWait(
-          server_connection_id));
-      time_wait_list_manager_->ProcessPacket(
-          packet_info.self_address, packet_info.peer_address,
-          server_connection_id, packet_info.form, GetPerPacketContext());
-
-      buffered_packets_.DiscardPackets(server_connection_id);
-    } else {
-      QUIC_RELOADABLE_FLAG_COUNT(quic_drop_invalid_small_initial_connection_id);
-      // Drop the packet silently.
-    }
+    // Drop the packet silently.
+    QUIC_CODE_COUNT(quic_dropped_invalid_small_initial_connection_id);
     return true;
   }
 

quic/core/quic_dispatcher_test.cc

diff --git a/quic/core/quic_dispatcher_test.cc b/quic/core/quic_dispatcher_test.cc
index 144bffb..edb7ee1 100644
--- a/quic/core/quic_dispatcher_test.cc
+++ b/quic/core/quic_dispatcher_test.cc
@@ -884,7 +884,6 @@
 }
 
 TEST_F(QuicDispatcherTest, ProcessPacketWithInvalidShortInitialConnectionId) {
-  SetQuicReloadableFlag(quic_drop_invalid_small_initial_connection_id, true);
   // Enable v47 otherwise we cannot create a packet with a short connection ID.
   SetQuicReloadableFlag(quic_enable_version_47, true);
   CreateTimeWaitListManager();
@@ -1336,7 +1335,6 @@
 // Packets with truncated connection IDs should be dropped.
 TEST_F(QuicDispatcherTestStrayPacketConnectionId,
        StrayPacketTruncatedConnectionId) {
-  SetQuicReloadableFlag(quic_drop_invalid_small_initial_connection_id, true);
   CreateTimeWaitListManager();
 
   QuicSocketAddress client_address(QuicIpAddress::Loopback4(), 1);