LGTM. In build.xml, I don't think you need to add -ea explicitly to devmode tests. Not wrong, but they're already on.
A bigger problem, but mine not yours, is that rietveld is (wrongly) basing this on http://google-web-toolkit, not on incubator, so the side-by-sides are all wrong. (I assume you used my wrapper around upload.py; I'll have to make it either auto-detect, or at least let you specify, which it is!) http://gwt-code-reviews.appspot.com/159805 -- http://groups.google.com/group/Google-Web-Toolkit-Contributors
