UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36

Example URL:
https://jsfiddle.net/EMLilianaIturribarria/aq5dx8co/

Steps to reproduce the problem:
1. Create an iframe
2. Create an iframe inside that created iframe
3. Insert a video in the last iframe

What is the expected behavior?
Fullscreen should work no matter how many nested iframes are.

What went wrong?
There is an error with fullscreen video, this error occurs when the video is a child of an iframe inside an iframe. 

Example:
https://jsfiddle.net/EMLilianaIturribarria/aq5dx8co/

Js Fiddle already wraps my iframe with an iframe.
if you check the iframe src in isolation on clicking watch this will toggle fullscreen.
however that doesnt work if it's inside an iframe.

Did this work before? N/A 

Is it a problem with Flash or HTML5? N/A

Does this work in other browsers? N/A

Chrome version: 68.0.3440.106  Channel: stable
OS Version: OS X 10.13.6
Flash Version: 

This was working on version 67