UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36

Steps to reproduce the problem:
1. Add a css transform to the parent element containing the video eg:```body { transform: translate(0, 0) }```
2. Click the menu options (...)
3. Menu options will not appear in correct position, in some cases will scroll you to the bottom of the page

What is the expected behavior?
Menu options should appear in correct position even if parent element has css transforms applied

What went wrong?
I believe this is due to the -internal-media-controls-overflow-menu-list element having a css position fixed. This means the element is not being positioned relative to the window but to the closest parent element with the css transform applied. 

While this is layout behaviour is in line with the css transform spec, I can imagine not being allowed to use a video element inside a parent with transforms is going to break a fair amount of websites. Have confirmed that clicking on the video options button in Slack's web app causes the whole page to scroll somewhere seemingly random.

Did this work before? Yes 66

Does this work in other browsers? Yes

Chrome version: 67.0.3396.99  Channel: stable
OS Version: OS X 10.13.5
Flash Version: 

Using position absolute on -internal-media-controls-overflow-menu-list fixes the issue. Have tried to select this via CSS but nothing seems to work.