We need to ensure that the WebGL content rendered is finished when it's accessed from the compositor thread to perform the composition. In order to that, we need to add a fence when a new WebGL buffer is pushed, and wait for that fence before the buffer is painted.
Pull request: https://github.com/WebKit/WebKit/pull/27252
Committed 277495@main (930c92835e20): <https://commits.webkit.org/277495@main> Reviewed commits have been landed. Closing PR #27252 and removing active labels.