Build the docker image and start the container.

Start `Xvfb` in the container via

```sh
$ /etc/init.d/xvfb start
```

Run Chrome with working WebGL in kiosk mode

```sh
$ google-chrome \
  --no-first-run \
  --user-data-dir=/tmp/chrome \
  --no-sandbox \
  --enable-logging=stderr \
  --use-gl=osmesa \
  --app=<some-url>
```
 
Open another shell into the container and take a screenshot:
 
```sh
$ import -window root screenshot.png
```
😎 Profit.