Deprecate quic_send_version_negotiation_fixed_bit

gfe-relnote: deprecate --gfe2_reloadable_flag_quic_send_version_negotiation_fixed_bit
PiperOrigin-RevId: 253919614
Change-Id: I8c28107def019e60543af16cf71fe20db2e27274

quic/core/quic_framer.cc

diff --git a/quic/core/quic_framer.cc b/quic/core/quic_framer.cc
index cc58806..b439ac0 100644
--- a/quic/core/quic_framer.cc
+++ b/quic/core/quic_framer.cc
@@ -1447,11 +1447,7 @@
   QuicDataWriter writer(len, buffer.get());
 
   // TODO(fayang): Randomly select a value for the type.
-  uint8_t type = static_cast<uint8_t>(FLAGS_LONG_HEADER);
-  if (GetQuicReloadableFlag(quic_send_version_negotiation_fixed_bit)) {
-    QUIC_RELOADABLE_FLAG_COUNT(quic_send_version_negotiation_fixed_bit);
-    type |= static_cast<uint8_t>(FLAGS_FIXED_BIT);
-  }
+  uint8_t type = static_cast<uint8_t>(FLAGS_LONG_HEADER | FLAGS_FIXED_BIT);
   if (!writer.WriteUInt8(type)) {
     return nullptr;
   }

quic/core/quic_framer_test.cc

diff --git a/quic/core/quic_framer_test.cc b/quic/core/quic_framer_test.cc
index bb57d0d..a3be0be 100644
--- a/quic/core/quic_framer_test.cc
+++ b/quic/core/quic_framer_test.cc
@@ -6718,13 +6718,9 @@
       // version tag
       QUIC_VERSION_BYTES,
   };
-  unsigned char type44 = 0x80;
-  if (GetQuicReloadableFlag(quic_send_version_negotiation_fixed_bit)) {
-    type44 = 0xC0;
-  }
   unsigned char packet44[] = {
       // type (long header)
-      type44,
+      0xC0,
       // version tag
       0x00, 0x00, 0x00, 0x00,
       // connection_id length
@@ -6761,14 +6757,10 @@
   // Client connection IDs cannot be used unless this flag is true.
   SetQuicRestartFlag(quic_do_not_override_connection_id, true);
 
-  unsigned char type_byte = 0x80;
-  if (GetQuicReloadableFlag(quic_send_version_negotiation_fixed_bit)) {
-    type_byte = 0xC0;
-  }
   // clang-format off
   unsigned char packet[] = {
       // type (long header)
-      type_byte,
+      0xC0,
       // version tag
       0x00, 0x00, 0x00, 0x00,
       // connection ID lengths

quic/core/quic_versions.cc

diff --git a/quic/core/quic_versions.cc b/quic/core/quic_versions.cc
index b85a13e..1c19cb1 100644
--- a/quic/core/quic_versions.cc
+++ b/quic/core/quic_versions.cc
@@ -434,7 +434,6 @@
   SetQuicReloadableFlag(quic_use_uber_loss_algorithm, true);
   SetQuicReloadableFlag(quic_use_uber_received_packet_manager, true);
   SetQuicReloadableFlag(quic_validate_packet_number_post_decryption, true);
-  SetQuicReloadableFlag(quic_send_version_negotiation_fixed_bit, true);
   SetQuicReloadableFlag(quic_no_client_conn_ver_negotiation, true);
   SetQuicReloadableFlag(quic_eliminate_static_stream_map_3, true);
   SetQuicReloadableFlag(quic_tolerate_reneging, true);