Track when QUIC connections are application limited. Protected by quic_enable_app_limited_check.

net/quic/core/quic_multipath_sent_packet_manager.cc

Index: net/quic/core/quic_multipath_sent_packet_manager.cc
diff --git a/net/quic/core/quic_multipath_sent_packet_manager.cc b/net/quic/core/quic_multipath_sent_packet_manager.cc
index ec3bb64f214ac1701e3ae1905f00e46ce2dffa95..0800a6ae4c82f92aeff71919d8ed64a9387dbd58 100644
--- a/net/quic/core/quic_multipath_sent_packet_manager.cc
+++ b/net/quic/core/quic_multipath_sent_packet_manager.cc
@@ -517,4 +517,14 @@ void QuicMultipathSentPacketManager::OnUnrecoverablePathError(
                                   ConnectionCloseSource::FROM_SELF);
 }
 
+void QuicMultipathSentPacketManager::OnApplicationLimited() {
+  for (PathSentPacketManagerInfo& path_manager_info : path_managers_info_) {
+    if (path_manager_info.manager == nullptr ||
+        path_manager_info.state != ACTIVE) {
+      continue;
+    }
+    path_manager_info.manager->OnApplicationLimited();
+  }
+}
+
 }  // namespace net