Alright. Make it a bit complicated then.
But as far as Safari and Chrome are concerned, actually it is all started in 1998 when an open source desktop environment project by the name of KDE designed the browser platform engine called 'WebKit' to be used primarily by a browser within KDE, Konqueror. If you are the user of a Unix-like operating system such as Linux, Unix, and BSD variances, you sure familiar with all these names.
Then Google joined the foray in 2005. Using the same WebKit engine, it designed a browser called 'Google Chrome' on the top of that. But shortly after, it realized that the WebKit is an open source initiative. Means, for everything that it takes and benefit from WebKit, it should give back to the community. Therefore, Google initiated an open source project by the name of 'Chromium Project', and still using WebKit.
On the other hand, every version of Google Chrome are actually the stable version of Chromium.
But if you use Chromium, you will notice that it uses less less resources and running quite faster than Chrome, Primarily this is because Chromium does not includes Google proprietary and tracking software in it. And if you quite a computer savvy person that always updating your machine, Chromium is definitely the answer, because they release new version known as snapshot on daily basis. There are a new version everyday.
You can get daily Chromium from HERE.