Revert "[video-raf] Enable video-raf by default"

This reverts commit bbe1b84e27fd45442c24e9a8bf6d067b47250be0.

Reason for revert: We no longer have 3 API OWNER LGTMS

Original change's description:
> [video-raf] Enable video-raf by default
> 
> This CL turns on HTMLVideoElement.requestAnimationFrame() by default.
> 
> Spec: https://wicg.github.io/video-raf/
> Blink-dev intent-to-ship: https://wicg.github.io/video-raf/
> WPT: https://wpt.fyi/results/video-raf
> 
> Bug: 1012063
> Change-Id: I5f44a430078e8272d2f9ebb1482e11e936697fb5
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2101242
> Commit-Queue: Thomas Guilbert <tguilbert@chromium.org>
> Commit-Queue: Chris Harrelson <chrishtr@chromium.org>
> Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
> Reviewed-by: Kenneth Russell <kbr@chromium.org>
> Auto-Submit: Thomas Guilbert <tguilbert@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#749965}

TBR=kbr@chromium.org,chrishtr@chromium.org,tguilbert@chromium.org

Change-Id: I0af2785d83863dea9943a491c3679874de0b8cb8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1012063
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2103391
Reviewed-by: Thomas Guilbert <tguilbert@chromium.org>
Commit-Queue: Thomas Guilbert <tguilbert@chromium.org>
Cr-Commit-Position: refs/heads/master@{#750291}