Firefox 69: TextTrack no longer loads cue files when disabled (#4579)
Firefox 69: TextTrack no longer loads cue files when disabled (#4579)

* Firefox 69: ::cue now limits permitted properties per spec
Previously, `::cue` allowed pretty much anything. Now the allowed
properties are limited per the spec.

Source:
* https://bugzilla.mozilla.org/show_bug.cgi?id=1321488

* Revert "Firefox 69: ::cue now limits permitted properties per spec"

This reverts commit 34712b7525e5cbc65b0c58e1bcee4a2ded404c44. Pushed
to the wrong branch.

* Firefox 69: TextTrack no longer loads cues if the mode is disabled
Instead, it loads them once the mode changes to either hidden or
started.

mdn/browser-compat-data,chrisdavidmills/browser-compat-data,chrisdavidmills/browser-compat-data,mdn/browser-compat-data