Simplify WebHostBuilderTests.CanUseCustomLoggerFactory.

- Keep all the code in the test itself, instead of in an
  extension method. Makes it easier to understand what's
  happening without having to look up the extension
  method's definition.

Author: Cesar Blum Silveira

test/Microsoft.AspNetCore.Hosting.Tests/Fakes/CustomLoggerFactory.cs

@@ -18,16 +18,6 @@ public void AddProvider(ILoggerProvider provider) { }
         public void Dispose() { }
     }
 
-    public static class CustomLoggerFactoryExtensions
-    {
-        public static IWebHostBuilder ConfigureCustomLogger(this IWebHostBuilder builder, Action<CustomLoggerFactory> configureLogger)
-        {
-            builder.UseLoggerFactory(_ => new CustomLoggerFactory());
-            builder.ConfigureLogging(configureLogger);
-            return builder;
-        }
-    }
-
     public class SubLoggerFactory : CustomLoggerFactory { }
 
     public class NonSubLoggerFactory : ILoggerFactory

test/Microsoft.AspNetCore.Hosting.Tests/WebHostBuilderTests.cs

@@ -294,7 +294,8 @@ public void ConfigureLoggingNotCalledIfLoggerFactoryTypeDoesNotMatches()
         public void CanUseCustomLoggerFactory()
         {
             var hostBuilder = new WebHostBuilder()
-                .ConfigureCustomLogger(factory =>
+                .UseLoggerFactory(_ => new CustomLoggerFactory())
+                .ConfigureLogging<CustomLoggerFactory>(factory =>
                 {
                     factory.CustomConfigureMethod();
                 })