Add initial scroll position hook to HTML spec

source

@@ -3904,6 +3904,7 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
       <li>The <dfn data-x-href="https://drafts.csswg.org/css-overflow/#propdef-overflow">'overflow'</dfn> property and its <dfn data-x-href="https://drafts.csswg.org/css-overflow/#valdef-overflow-hidden">'hidden'</dfn> value</li>
       <li>The <dfn data-x-href="https://drafts.csswg.org/css-overflow/#propdef-text-overflow">'text-overflow'</dfn> property</li>
       <li>The term <dfn data-x-href="https://drafts.csswg.org/css-overflow/#scroll-container">scroll container</dfn>
+      <li>The term <dfn data-x-href="https://drafts.csswg.org/css-overflow/#initial-scroll-position">initial scroll position</dfn>
     </ul>
 
     <p>The following terms and features are defined in <cite>CSS Positioned Layout</cite>:
@@ -4055,6 +4056,8 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
      <li>The <dfn data-x="event-scroll" data-x-href="https://drafts.csswg.org/cssom-view/#eventdef-document-scroll"><code>scroll</code></dfn> event</li>
      <li>The <dfn data-x="event-scrollend" data-x-href="https://drafts.csswg.org/cssom-view/#eventdef-document-scrollend"><code>scrollend</code></dfn> event</li>
      <li><dfn data-x-href="https://drafts.csswg.org/cssom-view/#set-up-browsing-context-features">set up browsing context features</dfn></li>
+     <li>The term <dfn data-x-href="https://drafts.csswg.org/cssom-view/#perform-a-scroll">perform a scroll</dfn></li>
+     <li>The term <dfn data-x-href="https://drafts.csswg.org/cssom-view/#scrolling-box">scrolling box</dfn></li>
     </ul>
 
     <p>The following features and terms are defined in <cite>CSS Syntax</cite>:
@@ -103722,6 +103725,9 @@ location.href = '#foo';</code></pre>
     <p>If <var>documentIsNew</var> is true, then:
 
     <ol>
+     <li><p><span>Update the initial scroll positions for scroll containers</span> in
+     <var>document</var>.</p></li>
+
      <li><p><span>Try to scroll to the fragment</span> for <var>document</var>.</p></li>
 
      <li><p>At this point <dfn>scripts may run for the newly-created document</dfn>
@@ -103879,6 +103885,31 @@ location.href = '#foo';</code></pre>
    </li>
   </ol>
 
+  <p>To <dfn>update the initial scroll positions for scroll containers</dfn> in a
+  <code>Document</code> <var>document</var>:</p>
+
+    <ol>
+     <li><p>Let <var>scrollers</var> be a <span>list</span> of all
+     <span data-x="scroll container">scroll containers</span> of <var>document</var>.<p></li>
+
+     <li>
+      <p><span data-x="list iterate">For each</span> <var>scroller</var> of <var>scrollers</var>:
+      </p>
+
+      <ol>
+       <li><p>If the user agent has reason to believe the user is no longer interested in scrolling
+       to <var>scroller</var>'s <span data-x="initial scroll position">initial scroll position
+       </span>, then abort these steps.</p></li>
+
+       <li><p>Let <var>position</var> be the <span data-x="initial scroll position">initial scroll
+       position</span> of <var>scroller</var>.</li>
+
+       <li><p><span data-x="perform a scroll">Perform a scroll</span> of <var>scroller</var>'s <span
+       data-x="scrolling box">scrolling box</span> to <var>position</var>.</p></li>
+      </ol>
+     </li>
+    </ol>
+
   <p>To <dfn export>make document unsalvageable</dfn>, given a <code>Document</code>
   <var>document</var> and a string <var>reason</var>:</p>
 
@@ -145050,6 +145081,7 @@ INSERT INTERFACES HERE
   Dave Singer,
   Dave Tapuska,
   Dave Townsend<!-- Mossop on moz irc -->,
+  David Awogbemila,
   David Baron,
   David Bloom,
   David Bokan,