Adding a text track makes controls visible
Created attachment 184767 [details]
Created attachment 184791 [details]
Updated patch as the first version sometimes creates hidden controls when we did not previously. This isn't really a change in functionality, but it causes some tests that dump the render tree to fail so attempt to restore the previous behavior.
Not marking r? so the bots can chew on it first.
Comment on attachment 184791 [details]
Attachment 184791 [details] did not pass chromium-ews (chromium-xvfb):
New failing tests:
Created attachment 184801 [details]
Oops, the results for my new test depended on the side effect I removed in the second patch :-O
Comment on attachment 184801 [details]