Add element.focus({ preventScroll: true })

Addresses the most basic part of whatwg#834, allowing further customizations
to be done by JavaScript code.

source

@@ -9984,7 +9984,7 @@ interface <dfn>HTMLElement</dfn> : <span>Element</span> {
   [<span>CEReactions</span>] attribute boolean <span data-x="dom-inert">inert</span>;
   void <span data-x="dom-click">click</span>();
   [<span>CEReactions</span>] attribute long <span data-x="dom-tabindex">tabIndex</span>;
-  void <span data-x="dom-focus">focus</span>();
+  void <span data-x="dom-focus">focus</span>(optional <span>FocusOptions</span> options);
   void <span data-x="dom-blur">blur</span>();
   [<span>CEReactions</span>] attribute DOMString <span data-x="dom-accessKey">accessKey</span>;
   readonly attribute DOMString <span data-x="dom-accessKeyLabel">accessKeyLabel</span>;
@@ -9993,6 +9993,7 @@ interface <dfn>HTMLElement</dfn> : <span>Element</span> {
 
   [<span>CEReactions</span>] attribute [TreatNullAs=EmptyString] DOMString <span data-x="dom-innerText">innerText</span>;
 };
+
 <span>HTMLElement</span> implements <span>GlobalEventHandlers</span>;
 <span>HTMLElement</span> implements <span>DocumentAndElementEventHandlers</span>;
 <span>HTMLElement</span> implements <span>ElementContentEditable</span>;
@@ -73581,6 +73582,10 @@ END:VCARD</pre>
 
   <h4>Focus management APIs</h4>
 
+  <pre class="idl">dictionary <dfn>FocusOptions</dfn> {
+  boolean <span data-x="dom-focusoptions-preventscroll">preventScroll</span> = false;
+};</pre>
+
   <dl class="domintro">
 
    <dt><var>document</var> . <code subdfn data-x="dom-document-activeElement">activeElement</code></dt>
@@ -73629,13 +73634,19 @@ END:VCARD</pre>
    </dd>
 -->
 
-   <dt><var>element</var> . <code subdfn data-x="dom-focus">focus</code>()</dt>
+   <dt><var>element</var> . <code subdfn data-x="dom-focus">focus</code>([ { <code
+    data-x="dom-focusoptions-preventscroll">preventScroll</code>: true } ])</dt>
 
    <dd>
 
     <p>Moves the focus to the element.</p>
 
-    <p>If the element is a <span>browsing context container</span>, moves the focus to the <span>nested browsing context</span> instead.</p>
+    <p>If the element is a <span>browsing context container</span>, moves the focus to the
+    <span>nested browsing context</span> instead.</p>
+
+    <p>By default, this method also scrolls the element into view. Providing the <code
+    data-x="dom-focusoptions-preventscroll">preventScroll</code> option and setting it to true
+    prevents this behavior.</p>
 
    </dd>
 
@@ -73733,8 +73744,8 @@ END:VCARD</pre>
   system widget (e.g. tab or window) that contained the <span>browsing context</span>, but hostile
   sites widely abuse this behavior to the user's detriment.</p>
 
-  <p>The <dfn data-dfn-for="HTMLElement"><code data-x="dom-focus">focus()</code></dfn> method on
-  elements, when invoked, must run the following algorithm:</p>
+  <p>The <dfn><code data-x="dom-focus">focus(<var>options</var>)</code></dfn> method on elements, when
+  invoked, must run the following steps:</p>
 
   <ol>
 
@@ -73744,6 +73755,13 @@ END:VCARD</pre>
 
    <li><p>Run the <span>focusing steps</span> for the element.</p></li>
 
+   <li><p>If the value of the <dfn><code
+   data-x="dom-focusoptions-preventscroll">preventScroll</code></dfn> dictionary member of
+   <var>options</var> is false, then <span data-x="scroll an element into view">scroll the element
+   into view</span> with scroll behavior "<code data-x="">auto</code>", block flow direction
+   position set to a UA-defined value, and inline base direction position set to a UA-defined
+   value.</p></li>
+
    <li><p>Unmark the element as <i data-x="locked for focus">locked for focus</i>.</p></li>
 
   </ol>
@@ -120514,6 +120532,7 @@ INSERT INTERFACES HERE
   Jessica Jong,
   jfkthame, <!-- GitHub -->
   Jian Li,
+  Jihye Hong,
   Jim Jewett,
   Jim Ley,
   Jim Meehan,