Insert the link:
chrome://policy
in the browser window.
Make sure there aren't any funny links loaded there. If they are, some variant of the weknow.ac virus may be running.
The solution is to remove all extensions from the there dots that are vertical menu on the far right, selecting the More Tools -> Extensions. Followed by quitting Chrome, and running the following command line in the Terminal App:
defaults write com.google.Chrome HomepageIsNewTabPage -bool false
defaults write com.google.Chrome NewTabPageLocation -string "https://www.google.com/"
defaults write com.google.Chrome HomepageLocation -string "https://www.google.com/"
defaults delete com.google.Chrome DefaultSearchProviderSearchURL
defaults delete com.google.Chrome DefaultSearchProviderNewTabURL
defaults delete com.google.Chrome DefaultSearchProviderName
Restart Chrome after a restart of the computer. If chrome://policy seems still infected, reload the policies, and quit and restart Chrome.
If this does not work, use http://www.etrecheck.com/
to determine if another memory resident program may be problematic.
Note: Chromium is a virus that looks like Chrome, and should be removed with a thorough malware removal session.