U4-7577 Remove dependency on UmbracoContext in CreateServiceContext / RequestLifespanMessagesFactory

src/Umbraco.Web/SingletonHttpContextAccessor.cs

@@ -0,0 +1,12 @@
+using System.Web;
+
+namespace Umbraco.Web
+{
+    internal class SingletonHttpContextAccessor : IHttpContextAccessor
+    {
+        public HttpContextBase Value
+        {
+            get { return new HttpContextWrapper(HttpContext.Current); }
+        }
+    }
+}