Revert WebSocketRequestedProtocols to IList<string>

Author: Tratcher

src/Microsoft.AspNet.Http.Abstractions/WebSocketManager.cs

@@ -1,17 +1,17 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System.Collections.Generic;
 using System.Net.WebSockets;
 using System.Threading.Tasks;
-using Microsoft.Framework.Primitives;
 
 namespace Microsoft.AspNet.Http
 {
     public abstract class WebSocketManager
     {
         public abstract bool IsWebSocketRequest { get; }
 
-        public abstract StringValues WebSocketRequestedProtocols { get; }
+        public abstract IList<string> WebSocketRequestedProtocols { get; }
 
         public virtual Task<WebSocket> AcceptWebSocketAsync()
         {

src/Microsoft.AspNet.Http/DefaultWebSocketManager.cs

@@ -2,10 +2,10 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.Net.WebSockets;
 using System.Threading.Tasks;
 using Microsoft.AspNet.Http.Features;
-using Microsoft.Framework.Primitives;
 using Microsoft.Net.Http.Headers;
 
 namespace Microsoft.AspNet.Http.Internal
@@ -39,7 +39,7 @@ public override bool IsWebSocketRequest
             }
         }
 
-        public override StringValues WebSocketRequestedProtocols
+        public override IList<string> WebSocketRequestedProtocols
         {
             get
             {