[webkit-changes] [WebKit/WebKit] d8b353: REGRESSION(257542 at main): Video is misaligned on Yo...

[Tim Nguyen]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: d8b353380562d051c4721fa092251ac922413bb6
      https://github.com/WebKit/WebKit/commit/d8b353380562d051c4721fa092251ac922413bb6
  Author: Tim Nguyen <ntim at apple.com>
  Date:   2023-02-28 (Tue, 28 Feb 2023)

  Changed paths:
    A LayoutTests/imported/w3c/web-platform-tests/fullscreen/model/move-fullscreen-element-expected.txt
    A LayoutTests/imported/w3c/web-platform-tests/fullscreen/model/move-fullscreen-element.html
    M Source/WebCore/dom/FullscreenManager.cpp

  Log Message:
  -----------
  REGRESSION(257542 at main): Video is misaligned on YouTube site's PiP player after transitioning from full screen
https://bugs.webkit.org/show_bug.cgi?id=253121
rdar://105713729

Reviewed by Ryosuke Niwa.

There is a bug with the fullscreen spec that leaves a dangling fullscreen flag when moving elements: https://github.com/whatwg/fullscreen/issues/217
This causes fullscreen styles to unintentionally apply on the YouTube site even though the player element which has moved in the DOM tree, has exited
fullscreen.

To fix this, we follow Chromium's pattern of running an extra "unfullscreen element" step in the synchronous exit fullscreen steps when the element to
be exited is disconnected.

* LayoutTests/imported/w3c/web-platform-tests/fullscreen/model/move-fullscreen-element-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/fullscreen/model/move-fullscreen-element.html: Added.
* Source/WebCore/dom/FullscreenManager.cpp:
(WebCore::FullscreenManager::exitFullscreen):

Canonical link: https://commits.webkit.org/260985@main