Chrome Version: (copy from chrome://version)
OS: (e.g. Win10, MacOS 10.12, etc...)

What steps will reproduce the problem?
(1) Open hangouts
(2) Send the link https://rebeccahughes.github.io/media/iframe_bug_page.html over hangouts
(3) Click the link to open the video in a new page

What is the expected result?
The video should not play since there has not been a user activation on the page.

What happens instead?
The video plays because the HasBeenActivated flag is returning true in Blink.

The HasBeenActivated flag is being checked by the iframe and is returning true on the main frame (which is a remote frame). This should be false as there has been no activation.

It only works if the iframe is on a different origin (so it looks like this could be related to site isolation).

If you enter the URL into the omnibox and hit enter the video will not play as the HasBeenActivated flag will correctly be false. It looks like it could be limited to renderer initiated navigations.