tray: Show warning in network tray when VPN or proxy used.

ash/system/network/network_list.h

Index: ash/system/network/network_list.h
diff --git a/ash/system/network/network_list.h b/ash/system/network/network_list.h
index c5615f31173bbc834854f47407e8118d24c1d7be..d306d9edad91fe8fb2bd420266ccc37bd489e393 100644
--- a/ash/system/network/network_list.h
+++ b/ash/system/network/network_list.h
@@ -29,6 +29,7 @@ namespace ash {
 
 struct NetworkInfo;
 class NetworkListDelegate;
+class TriView;
 
 // A list of available networks of a given type. This class is used for all
 // network types except VPNs. For VPNs, see the |VPNList| class.
@@ -117,6 +118,7 @@ class NetworkListView : public NetworkListViewBase,
   views::Separator* cellular_separator_view_;
   views::Separator* tether_separator_view_;
   views::Separator* wifi_separator_view_;
+  TriView* connection_warning_;
 
   // An owned list of network info.
   std::vector<std::unique_ptr<NetworkInfo>> network_list_;