Chrome does send domains/urls entered in the omnibar to google (I think someone did the experiment to test it several years ago), but sending out page content to google? If it were true it'll cause a huge legal and privacy problem, especially in places with tight privacy law like Europe.
Exactly, imagine if Google sends the page content after you log into your bank account.
And yet this is exactly what happens with automatic translation.
Microsoft did exactly that with their Bing toolbar.
The reason is Google's interest in advancing the web platform. They're afraid of content migrating into either native apps or Facebook, and Chrome is their (somewhat successful) attempt to make the open web competitive.