Has the problem been fixed? You could also try restoring your default Chrome settings if you go to Settings>Advanced and scroll all the way down to the bottom and choose reset settings. If that don't work I suggest downloading MalwareBytes antimalware free edition because you might have a spyware infection. All google searches seem to indicate this is a Mac spyware and there's a guide on removing it.
http://malwarewarrior.com/how-to-remove-chumsearch-com-hijacker/
Has the problem been fixed? You could also try restoring your default Chrome settings if you go to Settings>Advanced and scroll all the way down to the bottom and choose reset settings. If that don't work I suggest downloading MalwareBytes antimalware free edition because you might have a spyware infection. All google searches seem to indicate this is a Mac spyware and there's a guide on removing it.
http://malwarewarrior.com/how-to-remove-chumsearch-com-hijacker/