Isn’t Google Chrome just using the same rendering engine (Webkit) as Safari so you don’t have to test a site with Chrome if it works with Safari
Even if they all used the same JS engine, Graphics sub-systems, layout modules, parsers, storage systems, networking libraries, etc, you’d still have the problem that they’re not all using the same versions of those components.
Webkit is just a small piece of those browsers. It’s an important piece, but it’s not the whole story so, no, one Webkit-based browser is not the same as another Webkit-based browser.
And how is it good for the world for web sites like Google to own the browser? Won’t they use browser dominance to disadvantage web competitors like Yahoo?