What steps will reproduce the problem?
1. open the following webrtc example link https://webrtc.github.io/samples/src/content/devices/input-output/
2. see the MediaStreamTrack video track that we get from MediaStream with getUserMedia() is started as 'ended'
3.

What is the expected result?
that the MediaSteamTrack video track starts successfully and i should see my webcam footage 

What do you see instead?
a black screen and a MediaStreamTrack video track with 'ended' readyState

What version of the product are you using? On what operating system?
Version 61.0.3129.0 (Official Build) canary (64-bit)

Please provide any additional information below.
problem does not occur in Version 59.0.3071.86 (Official Build) (64-bit)
tried on 3 different computer 1 win7, 2 win10
work fine on 1 win10 computer and black screen on other 2 computer
restarting the computer didnt change anything
with 1 computer i tried after updating the canary (black screen) and other two was first install (1 black screen, 1 success case).