Chromium is a web browser based-on the (open) source code of Chrome. Google adds custom stuff atop the open parts of the Chromium code, but visually and operationally there isn't much difference between the two. You'll manually have to add flash (www.flash.com). Chrome add-ons work in Chromium.
Firefox is my preferred browser. It does what I need, and it's open source in every way. As with Chromium, you'll have to manually add Flash.
For Chromium, add the following extensions/add-ons: uBlock Origin, Flash Control, and Https Everywhere.