chromium/content/test/data/accessibility/display-locking/all.html

<!--
@BLINK-ALLOW:offscreen
@AURALINUX-ALLOW:visible
-->
<div>
  <div style="height:10000px;">spacer so that everything below will be offscreen (and won't get viewport-activated)</div>
  <div id="locked" style="content-visibility: auto">
    <div>child text will be in AX tree but without layout</div>
    <div id="nested" style="content-visibility: auto">
      nested activatable locked element will be in AX tree but without layout
    </div>
  </div>
  normal text 1
  <div id="nonViewportActivatable" hidden=until-found>
    nested non-viewport-activatable locked element will not be in AX tree
  </div>
  normal text 2
  <div id="nonActivatable" style="content-visibility: hidden">
    nested non-activatable locked element will not be in AX tree
  </div>
  normal text 3
</div>