Chromebooks just run a browser. Windows runs a browser and other things. Even if there aren't that many other things, your comment is fundamentally wrong.
Firefox and Chrome will have Metro versions on x86, but will have to interpret JavaScript under Windows RT, and V8 doesn't have an interpreted mode.
Edit: just to be clear, without VirtualAlloc() and VirtualProtect(), you can't really run any JIT. No LuaJIT, no PyPy, no Java. No Scala, Clojure, or jRuby either.