Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

external/aspnetwebstack/src/System.Web.Mvc/PreApplicationStartCode.cs

@@ -0,0 +1,28 @@
+// Copyright (c) Microsoft Corporation. All rights reserved. See License.txt in the project root for license information.
+
+using System.ComponentModel;
+using System.Web.WebPages.Scope;
+
+namespace System.Web.Mvc
+{
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public static class PreApplicationStartCode
+    {
+        private static bool _startWasCalled;
+
+        public static void Start()
+        {
+            // Guard against multiple calls. All Start calls are made on same thread, so no lock needed here
+            if (_startWasCalled)
+            {
+                return;
+            }
+            _startWasCalled = true;
+
+            WebPages.Razor.PreApplicationStartCode.Start();
+            WebPages.PreApplicationStartCode.Start();
+
+            ViewContext.GlobalScopeThunk = () => ScopeStorage.CurrentScope;
+        }
+    }
+}