Imported Upstream version 4.4.2.4

Former-commit-id: 92904c9c5915c37244316e42ba99e7b934ed7ee2

mcs/class/corlib/System.Security/SafeAccessTokenHandle.cs

@@ -0,0 +1,25 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace Microsoft.Win32.SafeHandles
+{
+	public sealed class SafeAccessTokenHandle : SafeHandle
+	{
+		public override bool IsInvalid {
+			get {
+				return handle == IntPtr.Zero;
+			}
+		}
+
+		public SafeAccessTokenHandle ()
+			: base (IntPtr.Zero, true)
+		{
+			
+		}
+
+		protected override bool ReleaseHandle()
+		{
+			return true;
+		}
+	}
+}