deleting /home/foo/.config/chromium worked for me as well. so, after upgrading from 12.04 to 12.10, it seems like a good idea to delete that directory.
other problems that seemed to be solved by deleting .config/chromium:
1. volume control remains synced while using webapps like pandora.com
2. no longer seeing unclosable unity icons in side menubar that were being left behind by chromium
deleting /home/foo/ .config/ chromium worked for me as well. so, after upgrading from 12.04 to 12.10, it seems like a good idea to delete that directory.
other problems that seemed to be solved by deleting .config/chromium:
1. volume control remains synced while using webapps like pandora.com
2. no longer seeing unclosable unity icons in side menubar that were being left behind by chromium