Some news sites had already conceded the need for this, with a separate "share in Gmail" link on their pages.
Interestingly enough, Firefox already had such a procedure built into the browser, and you can do the same in IE, but only through the use of the Google Toolbar.
Google says you'll get the above prompt the next time you visit Gmail in Chrome, but we had to logout before we saw the prompt. It's not unusual for a logout / login to be necessary to see changes in Gmail; we've seen that scenario before.
Note: the changes also mean you can set web calendar links to open in Chrome, too. You'll see a separate prompt for that.