Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

external/aspnetwebstack/src/Microsoft.Web.WebPages.OAuth/AuthenticationClientCollection.cs

@@ -0,0 +1,24 @@
+// Copyright (c) Microsoft Corporation. All rights reserved. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.ObjectModel;
+using DotNetOpenAuth.AspNet;
+
+namespace Microsoft.Web.WebPages.OAuth
+{
+    /// <summary>
+    /// A collection to store instances of IAuthenticationClient by keying off ProviderName.
+    /// </summary>
+    internal sealed class AuthenticationClientCollection : KeyedCollection<string, IAuthenticationClient>
+    {
+        public AuthenticationClientCollection()
+            : base(StringComparer.OrdinalIgnoreCase)
+        {
+        }
+
+        protected override string GetKeyForItem(IAuthenticationClient item)
+        {
+            return item.ProviderName;
+        }
+    }
+}