[System] Add NetworkCredential 4.0 construtors. Fixes #18005

mcs/class/System/System.Net/NetworkCredential.cs

@@ -1,12 +1,13 @@
 //
 // System.Net.NetworkCredential.cs
 //
-// Author: Duncan Mak ([email protected])
-// Author: Rolf Bjarne KVinge ([email protected])
+// Authors: Duncan Mak ([email protected])
+//          Rolf Bjarne KVinge ([email protected])
+//          Marek Safar ([email protected])
 //
 // (C) Ximian, Inc.
 // Copyright (C) 2010 Novell, Inc (http://www.novell.com)
-// Copyright (C) 2011 Xamarin Inc (http://www.xamarin.com)
+// Copyright (C) 2011, 2014 Xamarin Inc (http://www.xamarin.com)
 //
 // Permission is hereby granted, free of charge, to any person obtaining
 // a copy of this software and associated documentation files (the
@@ -56,12 +57,24 @@ namespace System.Net
 		}
 
 		public NetworkCredential (string userName, string password, string domain)
+			: this (userName, password)
 		{
-			this.userName = userName;
-			this.password = password;
 			this.domain = domain;
 		}
 
+#if NET_4_0
+		public NetworkCredential (string userName, SecureString password)
+		{
+			this.userName = userName;
+			SecurePassword = password;
+		}
+
+		public NetworkCredential (string userName, SecureString password, string domain)
+			: this (userName, password)
+		{
+			this.domain = domain;
+		}
+#endif
 		// Properties
 
 		public string Domain {