UserAgent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:63.0) Gecko/20100101 Firefox/63.0

Steps to reproduce the problem:
Current chromium-vaapi implementation supports jpeg, h264 and vp8 encoder.  It would be nice to have the vaapi vp9 encode accelerator too.

What is the expected behavior?

What went wrong?
N/A

Did this work before? N/A 

Does this work in other browsers? N/A

Chrome version: <Copy from: 'about:version'>  Channel: n/a
OS Version: 
Flash Version: 

This bug is to track the development of vaapi-vp9 encoder to avoid work duplication.