Deal with content-visibility during the layout loop.

Partially fixes #11210

Author: emilio

source

@@ -113769,44 +113769,21 @@ import "https://example.com/foo/../module2.mjs";</code></pre>
 
       <ol>
        <li><p>Let <var>resizeObserverDepth</var> be 0.</p></li>
+       <li><p>Let <var>updateNonInitialContentVisibilityAutoRelevancy</var> be true.</p></li>
 
        <li>
         <p>While true:</p>
 
         <ol>
          <li><p>Recalculate styles and update layout for <var>doc</var>.</p></li>
 
-         <li><p>Let <var>hadInitialVisibleContentVisibilityDetermination</var> be false.</p></li>
+         <li><p>Let <var>contentVisibilityChanged</var> be the result of calling <span>update
+         content relevancy for a document</span> with <var>doc</var> and
+         <var>updateNonInitialContentVisibilityAutoRelevancy</var>.</p></li>
 
-         <li>
-          <p>For each element <var>element</var> with <span
-          data-x="content-visibility-auto">'auto'</span> used value of
-          <span>'content-visibility'</span>:</p>
-
-          <ol>
-           <li><p>Let <var>checkForInitialDetermination</var> be true if <var>element</var>'s
-           <span>proximity to the viewport</span> is not determined and it is not <span>relevant to
-           the user</span>. Otherwise, let <var>checkForInitialDetermination</var> be
-           false.</p></li>
-
-           <li><p>Determine <span>proximity to the viewport</span> for <var>element</var>.</p></li>
+         <li><p>Set <var>updateNonInitialContentVisibilityAutoRelevancy</var> to false.</p></li>
 
-           <li><p>If <var>checkForInitialDetermination</var> is true and <var>element</var> is now
-           <span>relevant to the user</span>, then set
-           <var>hadInitialVisibleContentVisibilityDetermination</var> to true.</p></li>
-          </ol>
-         </li>
-
-         <li>
-          <p>If <var>hadInitialVisibleContentVisibilityDetermination</var> is true, then
-          <span>continue</span>.</p>
-
-          <p class="note">The intent of this step is for the initial viewport proximity
-          determination, which takes effect immediately, to be reflected in the style and layout
-          calculation which is carried out in a previous step of this loop. Proximity
-          determinations other than the initial one take effect at the next <span>rendering
-          opportunity</span>. <ref>CSSCONTAIN</ref></p>
-         </li>
+         <li><p>If <var>contentVisibilityChanged</var> is true, then <span>continue</span>.</p></li>
 
          <li><p><span>Gather active resize observations at depth</span>
          <var>resizeObserverDepth</var> for <var>doc</var>.</p></li>