UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.133 Safari/537.36

Steps to reproduce the problem:
1. Disable Google Cast via setting the policy "EnableMediaRouter" to false.

2. Tryin playing Twitch video https://www.twitch.tv/videos/130027442

What is the expected behavior?
Video plays.

What went wrong?
Video doesn't play.

Did this work before? N/A 

Chrome version: 57.0.2987.133  Channel: stable
OS Version: Fedora 25
Flash Version: Shockwave Flash 25.0 r0

According to https://www.chromium.org/administrators/policy-list-3#GoogleCast:

<<<<<<<<<<<<
Configure policies for Google Cast, a feature that allows users to send the contents of tabs, sites or the desktop from the browser to remote displays and sound systems.

If this policy is set to true or is not set, Google Cast will be enabled, and users will be able to launch it from the app menu, page context menus, media controls on Cast-enabled websites, and (if shown) the Cast toolbar icon.

If this policy set to false, Google Cast will be disabled.
>>>>>>>>>>>>

Thus, as far as I can tell, disabling the media router should prevent the user from *sending* a cast, not from *receiving* a cast.  (Or maybe this a bug in Twitch.tv's code, and Chrome itself is working as intended)