Convert QUIC non-feature flags to the old syntax, for consistency.

net/quic/core/congestion_control/bbr_sender.cc

Index: net/quic/core/congestion_control/bbr_sender.cc
diff --git a/net/quic/core/congestion_control/bbr_sender.cc b/net/quic/core/congestion_control/bbr_sender.cc
index 1bb7cdf17fe02b116c5f96ac9d119d5b539b0c68..19bab1e29f1acc06b24e1a485fa8091b90971587 100644
--- a/net/quic/core/congestion_control/bbr_sender.cc
+++ b/net/quic/core/congestion_control/bbr_sender.cc
@@ -99,14 +99,14 @@ BbrSender::BbrSender(const RttStats* rtt_stats,
       pacing_gain_(1),
       congestion_window_gain_(1),
       congestion_window_gain_constant_(
-          static_cast<float>(GetQuicFlag(FLAGS_quic_bbr_cwnd_gain))),
+          static_cast<float>(FLAGS_quic_bbr_cwnd_gain)),
       rtt_variance_weight_(
-          static_cast<float>(GetQuicFlag(FLAGS_quic_bbr_rtt_variation_weight))),
+          static_cast<float>(FLAGS_quic_bbr_rtt_variation_weight)),
       num_startup_rtts_(kRoundTripsWithoutGrowthBeforeExitingStartup),
-      congestion_window_gain_for_slow_delivery_(static_cast<float>(
-          GetQuicFlag(FLAGS_quic_bbr_slow_delivery_cwnd_gain))),
+      congestion_window_gain_for_slow_delivery_(
+          static_cast<float>(FLAGS_quic_bbr_slow_delivery_cwnd_gain)),
       threshold_multiplier_for_slow_delivery_(static_cast<float>(
-          GetQuicFlag(FLAGS_quic_bbr_slow_delivery_threshold_multiplier))),
+          FLAGS_quic_bbr_slow_delivery_threshold_multiplier)),
       cycle_current_offset_(0),
       last_cycle_start_(QuicTime::Zero()),
       is_at_full_bandwidth_(false),