Chromium is the open source web browser project from which Google Chrome draws its source code.[2] The project's hourly Chromium snapshots appear essentially similar[3] to the latest builds of Google Chrome aside from the omission of certain Google additions, most noticeable among them: Google's branding, auto-update mechanism, click-through licensing terms, usage-tracking, a built-in PDF viewer and bundling of the Adobe Flash Player. Chromium uses the WebKit layout engine.
 
http://en.wikipedia.org/wiki/Chromium_%28web_browser%29