Add ash UI for third-party VPNs

chromeos/network/network_state.h

Index: chromeos/network/network_state.h
diff --git a/chromeos/network/network_state.h b/chromeos/network/network_state.h
index db6a153678009f63d463c28d4a21ab0fa5bb9fee..7830cd1c0c08833f7189d10ca3918d9e535b513c 100644
--- a/chromeos/network/network_state.h
+++ b/chromeos/network/network_state.h
@@ -92,6 +92,7 @@ class CHROMEOS_EXPORT NetworkState : public ManagedState {
   const std::string& roaming() const { return roaming_; }
   const std::string& payment_url() const { return payment_url_; }
   bool cellular_out_of_credits() const { return cellular_out_of_credits_; }
+  const std::string& vpn_provider_id() const { return vpn_provider_id_; }
 
   // Returns true if |connection_state_| is a connected/connecting state.
   bool IsConnectedState() const;
@@ -180,6 +181,11 @@ class CHROMEOS_EXPORT NetworkState : public ManagedState {
   std::string payment_url_;
   bool cellular_out_of_credits_;
 
+  // Property that indicates a VPN's provider: An extension ID for networks
+  // using a third-party provider or an empty string for networks using the
+  // built-in OpenVPN and L2TP support.
+  std::string vpn_provider_id_;
+
   // TODO(pneubeck): Remove this once (Managed)NetworkConfigurationHandler
   // provides proxy configuration. crbug.com/241775
   base::DictionaryValue proxy_config_;