[webkit-changes] [WebKit/WebKit] f82dc7: REGRESSION(265043 at main): Fullscreen mode only show...

[Alan Baradlay]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: f82dc74981d8b65a808c9c9fa7f9af7496e51074
      https://github.com/WebKit/WebKit/commit/f82dc74981d8b65a808c9c9fa7f9af7496e51074
  Author: Alan Baradlay <zalan at apple.com>
  Date:   2023-07-25 (Tue, 25 Jul 2023)

  Changed paths:
    A LayoutTests/fullscreen/fullscreen-containing-block-change-expected.txt
    A LayoutTests/fullscreen/fullscreen-containing-block-change-with-continuation-expected.txt
    A LayoutTests/fullscreen/fullscreen-containing-block-change-with-continuation.html
    A LayoutTests/fullscreen/fullscreen-containing-block-change.html
    M Source/WebCore/dom/FullscreenManager.cpp

  Log Message:
  -----------
  REGRESSION(265043 at main): Fullscreen mode only shows video in some part of the screen on Twitter
https://bugs.webkit.org/show_bug.cgi?id=258907
rdar://111095697>

Reviewed by Simon Fraser and Tim Nguyen.

Add-to-top-layer changes containing block state which may affect geometry and requires layout to run.

This patch ensures that all the relevant pieces are marked for layout when transitioning to fullscreen including cases when a child frame initiates it.
It is essentially mimicking what out-of-flow type of containing block change triggers through styleDid/WillChange
e.g. when going from absolute to fix with a relative positioned ancestor.

(Test case credit goes to Tim Nguyen)

* LayoutTests/fullscreen/fullscreen-containing-block-change-expected.txt: Added.
* LayoutTests/fullscreen/fullscreen-containing-block-change-with-continuation-expected.txt: Added.
* LayoutTests/fullscreen/fullscreen-containing-block-change-with-continuation.html: Added.
* LayoutTests/fullscreen/fullscreen-containing-block-change.html: Added.
* Source/WebCore/dom/FullscreenManager.cpp:
(WebCore::markRendererDirtyAfterTopLayerChange):
(WebCore::FullscreenManager::willEnterFullscreen):

Canonical link: https://commits.webkit.org/266309@main