You can bet they will. The V8 engine is unlikely to present much of an obstacle. We have a large JS codebase and the Opera, WebKit (Safari), Spidermonkey (Gecko/Firebird), Rhino (Spidermonkey port to Java) and JScript (IE6/7) engines are no hassle to support.

The hard part is DOM interaction and styling. But as they're using WebKit and are putting a lot of effort into compatibility - this should be a breeze.

The really hard work is support for IE6. 1990s JS assumptions, very bad and inconsistent DOM behaviour, etc.

New, open JS engines with a different take on executing JS (Tamarin, V8) are wonderful news for JS developers everywhere. And consumers too, of course.