Get current domain root node in Umbraco content finder

gistfile1.txt

public class NewsContentFinder : IContentFinder
{
    public bool TryFindContent(PublishedContentRequest contentRequest)
    {
        if (contentRequest != null && contentRequest.HasDomain)
        {
            var rootDomainNode = contentRequest.RoutingContext.UmbracoContext.ContentCache.GetById(contentRequest.Domain.RootNodeId);
        }
    }
}