ServiceResolverAdapter: Allows you to use the ASP.NET MVC DependencyResolver for ASP.NET Web API

ModifiedNinjectWebCommon.cs

/// <summary>
/// Starts the application
/// </summary>
public static void Start() 
{
    DynamicModuleUtility.RegisterModule(typeof(OnePerRequestHttpModule));
    DynamicModuleUtility.RegisterModule(typeof(NinjectHttpModule));
    bootstrapper.Initialize(CreateKernel);
    System.Web.Http.GlobalConfiguration.Configuration.ServiceResolver.SetResolver(System.Web.Mvc.DependencyResolver.Current.ToServiceResolver());
}

ServiceResolverAdapter.cs

    public class ServiceResolverAdapter : System.Web.Http.Services.IDependencyResolver
    {
        private readonly System.Web.Mvc.IDependencyResolver dependencyResolver;

        public ServiceResolverAdapter(System.Web.Mvc.IDependencyResolver dependencyResolver)
        {
            if (dependencyResolver == null) throw new ArgumentNullException("dependencyResolver");
            this.dependencyResolver = dependencyResolver;
        }

        public object GetService(Type serviceType)
        {
            return dependencyResolver.GetService(serviceType);
        }

        public IEnumerable<object> GetServices(Type serviceType)
        {
            return dependencyResolver.GetServices(serviceType);
        }
    }

    public static class ServiceResolverExtensions
    {
        public static System.Web.Http.Services.IDependencyResolver ToServiceResolver(this System.Web.Mvc.IDependencyResolver dependencyResolver)
        {
            return new ServiceResolverAdapter(dependencyResolver);
        }
    }