Firefox 68: local files now treated as cross-origin (1558299)

[jscher2000]

@John_Bushakra

We are now seeing an issue playing instructional videos (mp4) from an tag. When accessing from both file:// and from http://,
we get a blank page, with no content, and no errors in the console. When accessing from https://, the video plays.

Video playback doesn’t involve the same privacy concerns as recording, so there’s no obvious reason for Firefox to treat them the same way.

I don’t notice a problem in a simple video tag where the source video is in the same directory (locally accessed on file://):

<video controls="controls" preload="none" width="560" height="320">
  <source src="big_buck_bunny.mp4" type="video/mp4">
</video>

That’s static HTML, not scripted, if that makes a difference.