Are these fixed types defined in a viz config?

I am wondering if using the relative params that the new activity API would be beneficial here. In that API if you use a 0 or negative number for `start` or `finish` then it assumes that you want a relative period from now. It has the benefit of pushing the time calculation of _now_ to the server and improving cachability /cc @acmcelwee 

```javascript
rolling: { start: -60, finish: 0 
```