Deprecate gfe2_reloadable_flag_quic_consider_original_connection_id_as_active_pre_handshake.

PiperOrigin-RevId: 463343975
diff --git a/quiche/quic/core/http/end_to_end_test.cc b/quiche/quic/core/http/end_to_end_test.cc
index 68c3d8c..d52ba93 100644
--- a/quiche/quic/core/http/end_to_end_test.cc
+++ b/quiche/quic/core/http/end_to_end_test.cc
@@ -4926,8 +4926,6 @@
 // Regression test for b/116200989.
 TEST_P(EndToEndTest,
        SendStatelessResetIfServerConnectionClosedLocallyDuringHandshake) {
-  SetQuicReloadableFlag(
-      quic_consider_original_connection_id_as_active_pre_handshake, true);
   connect_to_server_on_initialize_ = false;
   ASSERT_TRUE(Initialize());
 
diff --git a/quiche/quic/core/quic_connection.cc b/quiche/quic/core/quic_connection.cc
index 0f471c9..c7b634b 100644
--- a/quiche/quic/core/quic_connection.cc
+++ b/quiche/quic/core/quic_connection.cc
@@ -6913,11 +6913,6 @@
     QUICHE_DCHECK(version().HasIetfQuicFrames());
     result = self_issued_cid_manager_->GetUnretiredConnectionIds();
   }
-  if (GetQuicReloadableFlag(
-          quic_consider_original_connection_id_as_active_pre_handshake)) {
-    QUIC_RELOADABLE_FLAG_COUNT(
-        quic_consider_original_connection_id_as_active_pre_handshake);
-  }
   if (!original_destination_connection_id_.has_value()) {
     return result;
   }
@@ -6925,10 +6920,7 @@
   if (GetQuicRestartFlag(quic_map_original_connection_ids)) {
     QUIC_RESTART_FLAG_COUNT_N(quic_map_original_connection_ids, 4, 4);
     add_original_connection_id = true;
-  } else if (
-      !IsHandshakeComplete() &&
-      GetQuicReloadableFlag(
-          quic_consider_original_connection_id_as_active_pre_handshake)) {
+  } else if (!IsHandshakeComplete()) {
     QUIC_CODE_COUNT(quic_active_original_connection_id_pre_handshake);
     add_original_connection_id = true;
   }
diff --git a/quiche/quic/core/quic_flags_list.h b/quiche/quic/core/quic_flags_list.h
index 10f620f..15c6579 100644
--- a/quiche/quic/core/quic_flags_list.h
+++ b/quiche/quic/core/quic_flags_list.h
@@ -41,8 +41,6 @@
 QUIC_FLAG(quic_reloadable_flag_quic_fix_on_stream_reset, true)
 // If true, close the connection if a crypto send buffer exceeds its size limit.
 QUIC_FLAG(quic_reloadable_flag_quic_bounded_crypto_send_buffer, false)
-// If true, consider original connection ID as active before handshake completes.
-QUIC_FLAG(quic_reloadable_flag_quic_consider_original_connection_id_as_active_pre_handshake, true)
 // If true, default-enable 5RTO blachole detection.
 QUIC_FLAG(quic_reloadable_flag_quic_default_enable_5rto_blackhole_detection2, true)
 // If true, disable QUIC version Q043.