You cant do much. It is quite late already.
If you answer Yes to most of the questions then google already have tracking mechanism to track the things you said.
1) Your visitors are using google chrome
2) Your visitors are having chrome toolbar in other browsers
3) Your visitors are routed through or using GOOGLE DNS 8.8.8.8 & 8.8.4.4
If your client using google between them and your server, you cant do much already. I stopped thinking about this too much. However I was like you couple of years before
1) I don't have google analytics in my pages
2) I don't use chrome for my day to day searches. Only for different fb and twitter accounts and some incognito usage
3) I don't have google+ or scripts used in my pages
Now lately For point 3 I started adding google+ scripts and now I don't care much about google spying. You cant stop them. so no point fearing about google too much. However, I still did not add google analytics.