Set ViewBag from ActionFilterAttribute

The site I am creating custom colors that can be set by the user (only on certain pages). I want to grab that data within an ActionFilterAttribute and set it in the ViewBag so I can then get the data in my _Layout.cshtml.

Here is my ActionFilterAttribute...

public class PopulateColorOptionsAttribute : ActionFilterAttribute
{
    private readonly OptionsDataHelper optionsDataHelper;

    public PopulateOptionsAttribute(OptionsDataHelper optionsDataHelper)
    {
        this.optionsDataHelper = optionsDataHelper;
    }

    public override async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
    {
        await base.OnActionExecutionAsync(context, next);

        // Get the cemetery data and set it on the view bag.
        var personId = Convert.ToInt32(context.RouteData.Values["personId"]);
        context.Controller.ViewBag.OptionsData = await optionsDataHelper.GetValueAsync(personId, CancellationToken.None);
    }
}

Unfortunately, I receive an error on ViewBag that states:

'object' does not contain a definition for 'ViewBag' and no extension method 'ViewBag' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?) [dnx451]

I'm pretty sure I'm not understanding something correctly about Filters and I would appreciate guidance on how to achieve what I am looking to do.