I entered http://code.google.com/p/chromiumembedd ... ail?id=254 in the issue tracker this morning, for enhancing CEF to support IME-aware applications. I think some pictures will help to explain what my patch adds to CEF, so I've included a before and after shot below.
Before patching: non-auto-positioned IME window and lack of underlined composition.
After patching: auto-positioned IME window, current composition is underlined