Deprecate --gfe2_reloadable_flag_quic_key_update_supported.

PiperOrigin-RevId: 345546710
Change-Id: I6953863823294278c0c7a143dd9ef33439ca9770
diff --git a/quic/core/http/end_to_end_test.cc b/quic/core/http/end_to_end_test.cc
index df3b1f9..a7d714a 100644
--- a/quic/core/http/end_to_end_test.cc
+++ b/quic/core/http/end_to_end_test.cc
@@ -5025,8 +5025,6 @@
 }
 
 TEST_P(EndToEndTest, KeyUpdateInitiatedByClient) {
-  SetQuicReloadableFlag(quic_key_update_supported, true);
-
   if (!version_.UsesTls()) {
     // Key Update is only supported in TLS handshake.
     ASSERT_TRUE(Initialize());
@@ -5065,8 +5063,6 @@
 }
 
 TEST_P(EndToEndTest, KeyUpdateInitiatedByServer) {
-  SetQuicReloadableFlag(quic_key_update_supported, true);
-
   if (!version_.UsesTls()) {
     // Key Update is only supported in TLS handshake.
     ASSERT_TRUE(Initialize());
@@ -5138,8 +5134,6 @@
 }
 
 TEST_P(EndToEndTest, KeyUpdateInitiatedByBoth) {
-  SetQuicReloadableFlag(quic_key_update_supported, true);
-
   if (!version_.UsesTls()) {
     // Key Update is only supported in TLS handshake.
     ASSERT_TRUE(Initialize());
@@ -5220,7 +5214,6 @@
 
 TEST_P(EndToEndTest, KeyUpdateInitiatedByConfidentialityLimit) {
   SetQuicReloadableFlag(quic_enable_aead_limits, true);
-  SetQuicReloadableFlag(quic_key_update_supported, true);
   SetQuicFlag(FLAGS_quic_key_update_confidentiality_limit, 4U);
 
   if (!version_.UsesTls()) {
diff --git a/quic/core/quic_flags_list.h b/quic/core/quic_flags_list.h
index e5b2fa9..f9530bb 100644
--- a/quic/core/quic_flags_list.h
+++ b/quic/core/quic_flags_list.h
@@ -44,7 +44,6 @@
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_fix_willing_and_able_to_write2, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_goaway_with_max_stream_id, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_granular_qpack_error_codes, true)
-QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_key_update_supported, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_let_connection_handle_pings, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_new_priority_update_frame, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_pass_path_response_to_validator, false)
diff --git a/quic/core/quic_framer.cc b/quic/core/quic_framer.cc
index 4862d35..c9ebdbe 100644
--- a/quic/core/quic_framer.cc
+++ b/quic/core/quic_framer.cc
@@ -4279,9 +4279,6 @@
 void QuicFramer::SetKeyUpdateSupportForConnection(bool enabled) {
   QUIC_DVLOG(1) << ENDPOINT << "SetKeyUpdateSupportForConnection: " << enabled;
   support_key_update_for_connection_ = enabled;
-  if (enabled) {
-    QUIC_RELOADABLE_FLAG_COUNT(quic_key_update_supported);
-  }
 }
 
 void QuicFramer::DiscardPreviousOneRttKeys() {
diff --git a/quic/core/quic_session.cc b/quic/core/quic_session.cc
index 058c775..e60d5b9 100644
--- a/quic/core/quic_session.cc
+++ b/quic/core/quic_session.cc
@@ -153,8 +153,7 @@
     connection_->OnSuccessfulVersionNegotiation();
   }
 
-  if (GetQuicReloadableFlag(quic_key_update_supported) &&
-      GetMutableCryptoStream()->KeyUpdateSupportedLocally()) {
+  if (GetMutableCryptoStream()->KeyUpdateSupportedLocally()) {
     config_.SetKeyUpdateSupportedLocally();
   }
 
diff --git a/quic/core/quic_session_test.cc b/quic/core/quic_session_test.cc
index 943025a..78c7b1e 100644
--- a/quic/core/quic_session_test.cc
+++ b/quic/core/quic_session_test.cc
@@ -2271,24 +2271,14 @@
   ASSERT_TRUE(session_.connection()->can_receive_ack_frequency_frame());
 }
 
-TEST_P(QuicSessionTestClient, KeyUpdateFlagNotSet) {
-  SetQuicReloadableFlag(quic_key_update_supported, false);
-  EXPECT_CALL(*session_.GetMutableCryptoStream(), KeyUpdateSupportedLocally())
-      .Times(0);
-  session_.Initialize();
-  EXPECT_FALSE(session_.config()->KeyUpdateSupportedLocally());
-}
-
-TEST_P(QuicSessionTestClient, KeyUpdateNotSupportedLocallyAndFlagSet) {
-  SetQuicReloadableFlag(quic_key_update_supported, true);
+TEST_P(QuicSessionTestClient, KeyUpdateNotSupportedLocally) {
   EXPECT_CALL(*session_.GetMutableCryptoStream(), KeyUpdateSupportedLocally())
       .WillOnce(Return(false));
   session_.Initialize();
   EXPECT_FALSE(session_.config()->KeyUpdateSupportedLocally());
 }
 
-TEST_P(QuicSessionTestClient, KeyUpdateSupportedLocallyAndFlagSet) {
-  SetQuicReloadableFlag(quic_key_update_supported, true);
+TEST_P(QuicSessionTestClient, KeyUpdateSupportedLocally) {
   EXPECT_CALL(*session_.GetMutableCryptoStream(), KeyUpdateSupportedLocally())
       .WillOnce(Return(true));
   session_.Initialize();
diff --git a/quic/core/quic_versions.cc b/quic/core/quic_versions.cc
index af6bd18..b70d335 100644
--- a/quic/core/quic_versions.cc
+++ b/quic/core/quic_versions.cc
@@ -602,7 +602,6 @@
 void QuicVersionInitializeSupportForIetfDraft() {
   // Enable necessary flags.
   SetQuicRestartFlag(quic_enable_zero_rtt_for_tls_v2, true);
-  SetQuicReloadableFlag(quic_key_update_supported, true);
   SetQuicReloadableFlag(quic_send_version_negotiation_for_short_connection_ids,
                         true);
 }