Add support for reading-flow

source

@@ -80111,6 +80111,7 @@ dictionary <dfn dictionary>ToggleEventInit</dfn> : <span>EventInit</span> {
   element</span> is a <span>reading flow scope owner</span>.</p>
 
   <p>A <dfn data-x="non-participating-reading-flow-item">non-participating reading flow item</dfn> is
+
   a <span data-x="reading-flow-item">reading flow item</span> whose computed value of the
   <span>'display'</span> property is 'contents' or whose computed value of the
   <span>'position'</span> property is 'fixed' or 'absolute'.</p>
@@ -80783,6 +80784,22 @@ dictionary <dfn dictionary>ToggleEventInit</dfn> : <span>EventInit</span> {
     focusable</span>.</p>
    </li>
 
+   <li>
+    <p>If <var>candidate</var> is a <span data-x="reading-flow-item">reading flow item</span> or
+    null, <var>direction</var> is <i>forward</i>, and <var>starting point</var> is in a
+    <span>reading-flow focus navigation scope</span> <var>scope</var>, then let <var>new
+    candidate</var> be the result of running the <span>reading flow sequential navigation search
+    algorithm</span> with <var>candidate</var> as the first argument, <var>direction</var> as the
+    second, and <var>starting point</var>'s focus navigation <var>scope</var> as the third.</p>
+
+    <p>If <var>starting point</var> is a <span data-x="reading-flow-item">reading flow item</span>,
+    <var>direction</var> is <i>backward</i>, and <var>starting point</var> is in a
+    <span>reading-flow focus navigation scope</span> <var>scope</var>, then let <var>new
+    candidate</var> be the result of running the <span>reading flow sequential navigation search
+    algorithm</span> with <var>starting point</var> as the first argument, <var>direction</var> as
+    the second, and <var>starting point</var>'s focus navigation <var>scope</var> as the third.</p>
+   </li>
+
    <li>
     <p>If <var>candidate</var> is a <span>navigable container</span> with a non-null <span>content
     navigable</span>, then:</p>
@@ -80800,7 +80817,6 @@ dictionary <dfn dictionary>ToggleEventInit</dfn> : <span>EventInit</span> {
 
      <li><p>Otherwise, set <var>candidate</var> to <var>recursive candidate</var>.</p></li>
     </ol>
-   </li>
 
    <li><p>Return <var>candidate</var>.</p></li>
   </ol>