Deprecate gfe2_reloadable_flag_quic_queue_until_handshake_complete.

Removes one more use of QuicConnection's encryption_level_ variable.

PiperOrigin-RevId: 392460301
diff --git a/quic/core/quic_connection.cc b/quic/core/quic_connection.cc
index f92ee53..ce1d5a5 100644
--- a/quic/core/quic_connection.cc
+++ b/quic/core/quic_connection.cc
@@ -2700,19 +2700,12 @@
 
 bool QuicConnection::ShouldEnqueueUnDecryptablePacket(
     EncryptionLevel decryption_level, bool has_decryption_key) const {
-  if (!GetQuicReloadableFlag(quic_queue_until_handshake_complete) &&
-      encryption_level_ == ENCRYPTION_FORWARD_SECURE) {
-    // We do not expect to install any further keys.
-    return false;
-  }
   if (has_decryption_key) {
     // We already have the key for this decryption level, therefore no
     // future keys will allow it be decrypted.
     return false;
   }
-  if (GetQuicReloadableFlag(quic_queue_until_handshake_complete) &&
-      IsHandshakeComplete()) {
-    QUICHE_RELOADABLE_FLAG_COUNT(quic_queue_until_handshake_complete);
+  if (IsHandshakeComplete()) {
     // We do not expect to install any further keys.
     return false;
   }
diff --git a/quic/core/quic_flags_list.h b/quic/core/quic_flags_list.h
index 6ead891..85fb592 100644
--- a/quic/core/quic_flags_list.h
+++ b/quic/core/quic_flags_list.h
@@ -119,8 +119,6 @@
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_conservative_cwnd_and_pacing_gains, false)
 // If true, validate that peer owns the new address once the server detects peer migration or is probed from that address, and also apply anti-amplification limit while sending to that address.
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_server_reverse_validate_new_path3, true)
-// Queue packets to attempt decryption later until the handshake is complete.
-QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_queue_until_handshake_complete, true)
 // When the STMP connection option is sent by the client, timestamps in the QUIC ACK frame are sent and processed.
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_send_timestamps, false)
 // When true, QuicDispatcher will silently drop QUIC packets that have invalid flags.