GVR Unity SwitchToTracked2D

using System;
using System.Collections;
using UnityEngine;
using UnityEngine.XR;

public class VRModeSwitcher : MonoBehaviour
{
    public Transform MainCameraTransform;
    void OnEnable ()
    {
        StartCoroutine (SwitchToTracked2D ());
    }

    // 2D but also with head tracking enabled:
    IEnumerator SwitchToTracked2D ()
    {
        XRSettings.enabled = false;
        XRSettings.LoadDeviceByName ("cardboard");
        yield return null;
    }

    void Update ()
    {
        MainCameraTransform.localRotation = GvrVRHelpers.GetHeadRotation ();
    }
}