To opt-out of Google’s identified tracking, visit the Activity controls on Google’s My Account page, and uncheck the box next to “Include Chrome browsing history and activity from websites and apps that use Google services." You can also delete past activity from your account.
Links from that paragraph:
* Activity controls: https://myaccount.google.com/activitycontrols
* My account page: https://myaccount.google.com/
* Delete past activity: https://support.google.com/websearch/answer/465