Set popover invoker immediately after changing popover's visibility s…

…tate to "showing"

See
<whatwg#9383 (comment)>.

Fixes whatwg#9383.

source

@@ -82580,8 +82580,6 @@ dictionary <dfn dictionary>DragEventInit</dfn> : <span>MouseEventInit</span> {
 
    <li><p><span>Assert</span>: <var>element</var>'s <span>popover invoker</span> is null.</p></li>
 
-   <li><p>Set <var>element</var>'s <span>popover invoker</span> to <var>invoker</var>.</p></li>
-
    <li><p><span>Assert</span>: <var>element</var> is not in <var>document</var>'s <span>top
    layer</span>.</p></li>
 
@@ -82628,7 +82626,7 @@ dictionary <dfn dictionary>DragEventInit</dfn> : <span>MouseEventInit</span> {
      data-x="attr-popover">popover</code> attribute.</p></li>
 
      <li><p>Let <var>ancestor</var> be the result of running the <span>topmost popover
-     ancestor</span> algorithm given <var>element</var>.</p></li>
+     ancestor</span> algorithm given <var>element</var> and <var>invoker</var>.</p></li>
 
      <li><p>If <var>ancestor</var> is null, then set <var>ancestor</var> to
      <var>document</var>.</p></li>
@@ -82672,6 +82670,8 @@ dictionary <dfn dictionary>DragEventInit</dfn> : <span>MouseEventInit</span> {
    <li><p>Set <var>element</var>'s <span>popover visibility state</span> to <span
    data-x="popover-showing-state">showing</span>.</p></li>
 
+   <li><p>Set <var>element</var>'s <span>popover invoker</span> to <var>invoker</var>.</p></li>
+
    <li><p>Run the <span>popover focusing steps</span> given <var>element</var>.</p></li>
 
    <li><p>If <var>shouldRestoreFocus</var> is true and <var>element</var>'s <code
@@ -82959,7 +82959,8 @@ dictionary <dfn dictionary>DragEventInit</dfn> : <span>MouseEventInit</span> {
   false, and false.</p>
 
   <p>To find the <dfn>topmost popover ancestor</dfn>, given a <code>Node</code>
-  <var>newPopover</var>, perform the following steps. They return an <span data-x="HTML
+  <var>newPopover</var>, and <span data-x="HTML elements">HTML element</span>
+  <var>invoker</var> or null, perform the following steps. They return an <span data-x="HTML
   elements">HTML element</span> or null.</p>
 
   <div class="note">
@@ -83037,8 +83038,7 @@ dictionary <dfn dictionary>DragEventInit</dfn> : <span>MouseEventInit</span> {
    <li><p>Run <var>checkAncestor</var> given <var>newPopover</var>'s parent node within the
    <span>flat tree</span>.</p></li>
 
-   <li><p>Run <var>checkAncestor</var> given <var>newPopover</var>'s <span>popover
-   invoker</span>.</p></li>
+   <li><p>Run <var>checkAncestor</var> given <var>invoker</var>.</p></li>
 
    <li><p>return <var>topmostPopoverAncestor</var>.</p></li>
   </ol>