4.7 About page causes high CPU usage

[SergeyBiryukov]

Upon the upgrade to 4.7, some users ​reported a 100% CPU load after being redirected to the About page, apparently caused by three videos set to autoplay simultaneously​. Others made a point that it's also a bad UX for users with slow and/or limited mobile data plans.

We should try to fix it in 4.7.2 or at least avoid doing that for future releases.

[bor0]

Added patch that removes autoplay and loop for the videos in the about page.

[jbpaul17]

Patch looks good to me. @SergeyBiryukov or @voldemortensen are either of you good to own this and land it in 4.7.3?

[voldemortensen]

I think the patch looks great, although I'm not sure we need to remove the loop attribute. That's not really the problem. Having said that, I don't care either way if loop is removed. +1 on commit.

[afercia]

Replying to SergeyBiryukov:

We should try to fix it in 4.7.2 or at least avoid doing that for future releases.

I'd totally second this and recommend to always avoid video playing automatically, for accessibility reasons too.

[SergeyBiryukov]

In 40089:

About page: Remove autoplay and loop attributes on "Theme Starter Content", "Edit Shortcuts", and "Video Headers" videos, originally added as a part of [39512].

For UX and accessibility reasons, it's better to always avoid playing videos automatically.

Props bor0.
Fixes #39560.

[SergeyBiryukov]

In 40090:

About page: Remove autoplay and loop attributes on "Theme Starter Content", "Edit Shortcuts", and "Video Headers" videos, originally added as a part of [39512].

For UX and accessibility reasons, it's better to always avoid playing videos automatically.

Props bor0.
Merges [40089] to the 4.7 branch.
Fixes #39560.