Enable creating a ViewResult without requiring a view engine

[puncsky]

After "#597 Remove ActionResultHelper", helpers in ActionResultHelper are merged to Controller.cs.

We find that actually return new ViewResult(_serviceProvider, _viewEngine) in public ViewResult View(string view, object model) is useless. And return new ViewResult() is enough because ViewResult itself has DI on its ctor and the services can be reached through Context.ApplicationServices.

[yishaigalatzer]

1. Make sure we don't get rid of the overload that takes in a view engine, because that's a way to customize the view result.
2. We should discuss this, as this is an anti pattern to DI and should only be used in specific cases (like when we want to be lazy). Speaking of lazy there is a very similar pattern in view components, where we take the full set of services (including view engine) where we are many times not going to use it.

[rynowak]

The advantage of it would be the ability to just say new ViewResult(MyModel) for POCO scenarios.

We could keep both overloads but it's a little strange to have an optional service passed.

[yishaigalatzer]

@rynowak I see your point. Lets get together with @loudej and discuss the design alternatives.

[pranavkm]

I had to deal with this when working with Activate (https://github.com/aspnet/Mvc/pull/648/files#r13678472). A POCO controller is forced to activate the service provider + ViewEngine to be able to produce a View rather than call the view result which eventually does have enough knowledge to obtain these values.

[yishaigalatzer]

@rynowak lets do it, touch base with @loudej but this keeps coming up.

[rynowak]

this is happening.