Add using statement for extension methods.

samples/MvcSample.Web/HomeController.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Linq;
+using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Mvc;
 using Microsoft.AspNet.Mvc.Rendering;
 using MvcSample.Web.Models;

test/Microsoft.AspNet.Mvc.Core.Test/ActionResults/ObjectContentResultTests.cs

@@ -3,6 +3,7 @@
 
 using System.Collections.Generic;
 using System.IO;
+using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Mvc.Internal;
@@ -48,7 +49,7 @@ namespace Microsoft.AspNet.Mvc.Core.Test.ActionResults
             // Assert
             httpResponse.VerifySet(r => r.ContentType = expectedContentType);
             // The following verifies the correct Content was written to Body
-            httpResponse.Verify(o => o.WriteAsync(input), Times.Exactly(1));
+            httpResponse.Verify(o => o.WriteAsync(input, CancellationToken.None), Times.Exactly(1));
         }
 
         [Fact]

test/WebSites/ActivatorWebSite/Controllers/RegularController.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Mvc;
 
 namespace ActivatorWebSite

test/WebSites/BasicWebSite/Controllers/HomeController.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System.Threading.Tasks;
+using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Mvc;
 
 namespace BasicWebSite.Controllers