UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.79 Safari/537.36

Example URL:
http://video.webmfiles.org/big-buck-bunny_trailer.webm

Steps to reproduce the problem:
1. Download the raw build for Chromium for Linux x86 at download-chromium.appspot.com
2. Run Linux SUID Sandbox command under 'Installation instructions for “Raw builds of Chromium”
https://chromium.googlesource.com/chromium/src/+/master/docs/linux_suid_sandbox_development.md
3. Confirm version 51.0.2684.0 
4. Run the example WEBM video

What is the expected behavior?
The audio plays but not the video file.  The user sees a black screen.  No error messages indicated in Console.

What went wrong?
The WEBM video plays audio but not the actual video portion.

Did this work before? N/A 

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

Does this work in other browsers? Yes 

Chrome version: 51.0.2684.0  Channel: stable
OS Version: Ubuntu 14.04 LTS x32
Flash Version: Adobe Flash Player 11.2

I was able to run WEBM on the most recent raw build of Chromium for Linux x 64 (version 53.0.2758.0)