It seems Google has an open source browser project.
I believe this must be true because a comic strip on the web told me so. While I was reading this comic I wasn't sure what amazed me more, the interesting things I was learning about the technical design of Chrome (the Browser), or the fact that I was enjoying learning about the technical design of Chrome from comic characters.
Seriously though, it sounds like the rendering is to be done by Webkit, so perhaps too, the exposure of ARIA semantics in the DOM to desktop Accessibility API will eventually come from Webkit. Of course Firefox has pioneered this stuff, but Aaron is helping the other browsers as much as he can. Today, ARIA is a crucial piece of pushing the web as an application platform.
Thanks for reading.