Add IW03, IW10, IW20, and IW50 experiments to Chrome Canary and add flag counts.

PiperOrigin-RevId: 397848255
diff --git a/quic/core/quic_sent_packet_manager.cc b/quic/core/quic_sent_packet_manager.cc
index fd1190b..d9d384f 100644
--- a/quic/core/quic_sent_packet_manager.cc
+++ b/quic/core/quic_sent_packet_manager.cc
@@ -257,18 +257,22 @@
   // Initial window.
   if (GetQuicReloadableFlag(quic_unified_iw_options)) {
     if (config.HasClientRequestedIndependentOption(kIW03, perspective)) {
+      QUIC_RELOADABLE_FLAG_COUNT_N(quic_unified_iw_options, 1, 4);
       initial_congestion_window_ = 3;
       send_algorithm_->SetInitialCongestionWindowInPackets(3);
     }
     if (config.HasClientRequestedIndependentOption(kIW10, perspective)) {
+      QUIC_RELOADABLE_FLAG_COUNT_N(quic_unified_iw_options, 2, 4);
       initial_congestion_window_ = 10;
       send_algorithm_->SetInitialCongestionWindowInPackets(10);
     }
     if (config.HasClientRequestedIndependentOption(kIW20, perspective)) {
+      QUIC_RELOADABLE_FLAG_COUNT_N(quic_unified_iw_options, 3, 4);
       initial_congestion_window_ = 20;
       send_algorithm_->SetInitialCongestionWindowInPackets(20);
     }
     if (config.HasClientRequestedIndependentOption(kIW50, perspective)) {
+      QUIC_RELOADABLE_FLAG_COUNT_N(quic_unified_iw_options, 4, 4);
       initial_congestion_window_ = 50;
       send_algorithm_->SetInitialCongestionWindowInPackets(50);
     }