It will be useful for screenshots taken with layer borders enabled to indicate if UI-side compositing is in use, so use a different border color for page tiles.
<rdar://problem/104844082>
Pull request: https://github.com/WebKit/WebKit/pull/9358
Committed 259637@main (288bbe866276): <https://commits.webkit.org/259637@main> Reviewed commits have been landed. Closing PR #9358 and removing active labels.