Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.ServiceModel/System/ServiceModel/Channels/SecurityHeaderLayout.cs

@@ -0,0 +1,35 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//-----------------------------------------------------------------------------
+namespace System.ServiceModel.Channels
+{
+    using System.ComponentModel;
+
+    public enum SecurityHeaderLayout
+    {
+        Strict = 0,
+        Lax = 1,
+        LaxTimestampFirst = 2,
+        LaxTimestampLast = 3
+    }
+
+    static class SecurityHeaderLayoutHelper
+    {
+        public static bool IsDefined(SecurityHeaderLayout value)
+        {
+            return (value == SecurityHeaderLayout.Lax
+            || value == SecurityHeaderLayout.LaxTimestampFirst
+            || value == SecurityHeaderLayout.LaxTimestampLast
+            || value == SecurityHeaderLayout.Strict);
+        }
+
+        public static void Validate(SecurityHeaderLayout value)
+        {
+            if (!IsDefined(value))
+            {
+                throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new InvalidEnumArgumentException("value", (int)value,
+                    typeof(SecurityHeaderLayout)));
+            }
+        }
+    }
+}