Keep Hangouts from opening links inside the same task?
This started happening to me too recently. All links in Hangouts messages, when clicked, open in what appears to be a Hangouts-integrated browser. There is NO option to change this behavior.

It is definitely just an embedded instance of the Chrome browser - if you disable the Chrome app entirely, tapping a link in Hangouts gives you the normal "open with" dialog, and you can choose a default (I like the Adblock browser). But with the Chrome browser disabled you can't browse Google Play or update apps. And if you simply re-enable Chrome, it goes right back to opening links in Chrome and silently wipes out the choice of default that you just made.