Provide a chrome --headless & Xvfb-free image

[elgalu]

Refs:
PhantomJS' solo maintainer is leaving because of headless chrome
https://groups.google.com/forum/#!topic/phantomjs/9aI5d-LDuNE

https://news.ycombinator.com/item?id=14101233

To force the VM to keep it GC'd below 500mb

--js-flags="--max-old-space-size=500"

Drawbacks

• VNC won't be possible
• Video recording won't be possible

So it should be a separate image.

[elgalu]

This feature would be better to get implemented in the official docker-selenium as this project is intended to be used by Zalenium where live preview and video recording are core features of it.

[elgalu]

Already done by https://github.com/yukinying/chrome-headless-browser-docker