I have Firefox and Google Chrome installed in the same machine (Linux). It happens when I type something in Chrome Omnibox it suggests pages I have already visited in Firefox.
- I have never connected the accounts of both browsers
- I have never imported information from one browser to other
- I have never visited the suggested pages in Chrome
- The keyword I type in the omnibox is vague and there is no way it could guess the suggestion without having access to the Firefox history. i.e.: i type "ir" in Chrome and it suggests me the same Iron Maiden lyrics page I have browse before in Firefox.