Google allows you to retain copyright over your content. That's great. So if you send a copy of your manuscript to your publisher using Chrome, you technically will always be "the owner." You can still earn royalties from your content, and enter into contracts with publishers or other parties that want to license your content.

But Google will still have a "perpetual, irrevocable, worldwide, royalty-free, and non-exclusive licence to reproduce, adapt, modify, translate, publish, publicly perform, publicly display and distribute any Content which you submit, post or display on or through" the browser.

Usually, when we own rights to something, it gives us the power to do all those things without being bothered by someone else.

So in layman's terms, this essentially makes them "co-owner" of your content. They can license it to others, collect revenues (albeit not technically "royalties") from its sale, copy it at will, alter it at will. They don't have to have your permission to do any of this.

And that's just the intellectual property side. Forget about privacy with regard to your personal life or with regard to trade secrets.