Disable autoplay

[jonathansampson]

Test plan

A.

1. Go to https://www.w3schools.com/tags/tryit.asp?filename=tryhtml5_video_autoplay
2. Video should not autoplay
3. Click bravey panel to allow autoplay
4. Video should autoplay

B.

1. Go to youtube and watch a video
2. Video should not autoplay
3. Click bravey panel to allow autoplay
4. Video should autoplay

C. Also covered by automatic test

---

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).

Test Plan:

Resolves #7663
Resolves #2227
Resolves #4045

[darkdh]

There should be a global default setting of autoplay preference.

[jonathansampson]

@darkdh You mean, a switch inside about:preferences#shields?

[darkdh]

yeah, we should let users choose control the default global setting of it

[bridiver]

can we add tests for this? Preferably using a localhost url and not a remote site
otherwise ++

[jonathansampson]

@darkdh Global setting is now set.
@bridiver Working on test(s) next.

[jonathansampson]

@bridiver Spectron tests aren't running on Windows. I'm going to try and get it working on my Ubuntu VM, but it could be a day or two. Would you be okay with us merging prior to landing tests?

[darkdh]

I can help adding the test from Mac

[jonathansampson]

@darkdh That would be awesome! Thanks 🙂

[gary-schiltz]

I would also like to see the ability to control the preloading of HTML5 videos, since it consumes bandwidth, even if the user has no intention of watching a video. The desired behavior would be for the browser to act as if the preload attribute of all