This method has been completely unused for many years, possibly as far back as PR 8030, hence we can avoid shipping a little bit of dead code.
*Note:* If there's any third-party code depending on it, updating it ought to be as simple as changing
```javascript
const r = viewport.convertToViewportRectangle(rect);
```
into
```javascript
const r = [
...viewport.convertToViewportPoint(rect[0], rect[1]),
...viewport.convertToViewportPoint(rect[2], rect[3])
];
```
This is necessary to prevent import cycles with the next patch.
It also shouldn't hurt to reduce the size of `src/display/display_utils.js` a little bit, since utility-files have a tendency to increase in size over time.
