[UnifiedPDF] Zooming via HUD buttons, keyboard, and context menu
<rdar://problem/119632377>
Pull request: https://github.com/WebKit/WebKit/pull/23087
Committed 273342@main (12f1eb0ad174): <https://commits.webkit.org/273342@main> Reviewed commits have been landed. Closing PR #23087 and removing active labels.