Update: May 16
Today, I found that while Bing comes up as a default web page in Chrome, but the "homepage" at the top was "homepage-web.com". It also showed up in Chrome history again. I was able to get rid of this by following the instructions in Chrome help (go to Settings), and then doing one more Windows 8.1 Restart. So this appears to be a minor "bloatware" infection that got past Webroot at first. I'm checking to see if this should be flagged during screening.
Webroot says that it does not flag these as threat, but as PUA's, "potentially unwanted programs".