UserAgent: Mozilla/5.0 (X11; CrOS x86_64 8737.1.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2837.0 Safari/537.36
Platform: 54.0.2837.0 (Official Build) dev (64-bit)

Example URL:
https://www.youtube.com/watch?v=jC8Xy3Q82hY

Steps to reproduce the problem:
1. Open Youtube
2. Try to play a video

What is the expected behavior?
Video plays

What went wrong?
Video doesn't play

Did this work before? Yes 

Is it a problem with Flash or HTML5? Both

Does this work in other browsers? Yes 

Chrome version: 54.0.2837.0  Channel: dev
OS Version: 8737.1.0
Flash Version: Shockwave Flash 23.0 r0

Youtube fails

All tests pass here: http://www.quirksmode.org/html5/tests/video.html

Flas video fails as well: http://www.chemgapedia.de/vsengine/help/en/flash/