Deprecate gfe2_reloadable_flag_quic_bbr_slower_startup3.

gfe-relnote: n/a (Flag deprecation)
PiperOrigin-RevId: 253789248
Change-Id: I60fbed57d294d397878df317a4ea0b0507d2be8d

quic/core/congestion_control/bbr_sender.cc

diff --git a/quic/core/congestion_control/bbr_sender.cc b/quic/core/congestion_control/bbr_sender.cc
index c455751..858e57d 100644
--- a/quic/core/congestion_control/bbr_sender.cc
+++ b/quic/core/congestion_control/bbr_sender.cc
@@ -310,21 +310,15 @@
     QUIC_RELOADABLE_FLAG_COUNT(quic_bbr_flexible_app_limited);
     flexible_app_limited_ = true;
   }
-  if (GetQuicReloadableFlag(quic_bbr_slower_startup3) &&
-      config.HasClientRequestedIndependentOption(kBBQ1, perspective)) {
-    QUIC_RELOADABLE_FLAG_COUNT_N(quic_bbr_slower_startup3, 1, 4);
+  if (config.HasClientRequestedIndependentOption(kBBQ1, perspective)) {
     set_high_gain(kDerivedHighGain);
     set_high_cwnd_gain(kDerivedHighGain);
     set_drain_gain(1.f / kDerivedHighGain);
   }
-  if (GetQuicReloadableFlag(quic_bbr_slower_startup3) &&
-      config.HasClientRequestedIndependentOption(kBBQ2, perspective)) {
-    QUIC_RELOADABLE_FLAG_COUNT_N(quic_bbr_slower_startup3, 2, 4);
+  if (config.HasClientRequestedIndependentOption(kBBQ2, perspective)) {
     set_high_cwnd_gain(kDerivedHighCWNDGain);
   }
-  if (GetQuicReloadableFlag(quic_bbr_slower_startup3) &&
-      config.HasClientRequestedIndependentOption(kBBQ3, perspective)) {
-    QUIC_RELOADABLE_FLAG_COUNT_N(quic_bbr_slower_startup3, 3, 4);
+  if (config.HasClientRequestedIndependentOption(kBBQ3, perspective)) {
     enable_ack_aggregation_during_startup_ = true;
   }
   if (GetQuicReloadableFlag(quic_bbr_slower_startup4) &&

quic/core/congestion_control/bbr_sender_test.cc

diff --git a/quic/core/congestion_control/bbr_sender_test.cc b/quic/core/congestion_control/bbr_sender_test.cc
index 5a7ee40..6627851 100644
--- a/quic/core/congestion_control/bbr_sender_test.cc
+++ b/quic/core/congestion_control/bbr_sender_test.cc
@@ -475,7 +475,6 @@
 // Test the number of losses incurred by the startup phase in a situation when
 // the buffer is less than BDP, with a STARTUP CWND gain of 2.
 TEST_F(BbrSenderTest, PacketLossOnSmallBufferStartupDerivedCWNDGain) {
-  SetQuicReloadableFlag(quic_bbr_slower_startup3, true);
   CreateSmallBufferSetup();
 
   SetConnectionOption(kBBQ2);
@@ -620,7 +619,6 @@
 // TODO(wub): Re-enable this test once default drain_gain changed to 0.75.
 // Verify that the DRAIN phase works correctly.
 TEST_F(BbrSenderTest, DISABLED_ShallowDrain) {
-  SetQuicReloadableFlag(quic_bbr_slower_startup3, true);
   // Disable Ack Decimation on the receiver, because it can increase srtt.
   QuicConnectionPeer::SetAckMode(receiver_.connection(), AckMode::TCP_ACKING);
 
@@ -1171,7 +1169,6 @@
 }
 
 TEST_F(BbrSenderTest, DerivedPacingGainStartup) {
-  SetQuicReloadableFlag(quic_bbr_slower_startup3, true);
   CreateDefaultSetup();
 
   SetConnectionOption(kBBQ1);
@@ -1199,7 +1196,6 @@
 }
 
 TEST_F(BbrSenderTest, DerivedCWNDGainStartup) {
-  SetQuicReloadableFlag(quic_bbr_slower_startup3, true);
   CreateSmallBufferSetup();
 
   SetConnectionOption(kBBQ2);
@@ -1232,7 +1228,6 @@
 }
 
 TEST_F(BbrSenderTest, AckAggregationInStartup) {
-  SetQuicReloadableFlag(quic_bbr_slower_startup3, true);
   // Disable Ack Decimation on the receiver to avoid loss and make results
   // consistent.
   QuicConnectionPeer::SetAckMode(receiver_.connection(), AckMode::TCP_ACKING);

quic/quartc/quartc_factory.cc

diff --git a/quic/quartc/quartc_factory.cc b/quic/quartc/quartc_factory.cc
index a0affb5..4a85e57 100644
--- a/quic/quartc/quartc_factory.cc
+++ b/quic/quartc/quartc_factory.cc
@@ -84,7 +84,6 @@
   // SetQuicReloadableFlag() gets stubbed out.
   SetQuicReloadableFlag(quic_bbr_less_probe_rtt, true);   // Enable BBR6,7,8.
   SetQuicReloadableFlag(quic_unified_iw_options, true);   // Enable IWXX opts.
-  SetQuicReloadableFlag(quic_bbr_slower_startup3, true);  // Enable BBQX opts.
   SetQuicReloadableFlag(quic_bbr_flexible_app_limited, true);  // Enable BBR9.
 }