[webkit-changes] [WebKit/WebKit] a465a8: Web Inspector: Regression(260175 at main) Grid overla...

[Patrick Angle]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: a465a8a38ab52cfd57d2c2e710d72ea6f53d9c81
      https://github.com/WebKit/WebKit/commit/a465a8a38ab52cfd57d2c2e710d72ea6f53d9c81
  Author: Patrick Angle <pangle at apple.com>
  Date:   2023-04-12 (Wed, 12 Apr 2023)

  Changed paths:
    M LayoutTests/inspector/dom/showGridOverlay.html
    M Source/WebCore/inspector/InspectorOverlay.cpp

  Log Message:
  -----------
  Web Inspector: Regression(260175 at main) Grid overlay for grids using repeat syntax triggers assert performing downcast
https://bugs.webkit.org/show_bug.cgi?id=255311
rdar://107764654

Reviewed by Devin Rousso.

After 260175 at main, CSSGridIntegerRepeatValue and CSSGridAutoRepeatValue no longer inherit from CSSValueList, and instead
inherit from CSSValueContainingVector. The inspector overlay code was written in such a way that we were checking if the
class was one of the repeat types, but then downcasting to CSSValueList making that relation less apparent. Converting
the downcasts to dynamicDowncasts where we previously had the `is` checks fixes the issue and guards against this
mistake in the future.

* LayoutTests/inspector/dom/showGridOverlay.html:
* Source/WebCore/inspector/InspectorOverlay.cpp:
(WebCore::authoredGridTrackSizes):

Canonical link: https://commits.webkit.org/262869@main