For those who come here I'll explain how to fix annoying problem with replacement of genuine google search from the omnibox.
If this pic seems similar for you and you doesn't know hot to fix it , let me explain how to deal with it.
So,for some reason your default search engine was changed to this ugly custom search.
How I understood , it is some affiliate program of Google.
The problem when we trying to change the Search Options we couldn't do this because – "This setting is enforced by your administrator" and button not labeled for accessibility .
So it hardcoded in some configuration file.
In my case – (Using ubuntu linux) , we will looking file named – chrome.json
you can find this file with terminal using command
I found in – /etc/opt/chrome/policies/managed/chrome.json
lets look into
Save the file and trouble is fixed.(You may to restart the browser)
For Windows Users I can advice to use this link for solution ot this problem.