Bikeshed update for 'Use document.scrollingElement where appropriate (#33)

Fixes #14' [ci skip]

Generated from:

commit 77803dc
Author: Stephen McGruer <stephen.mcgruer@gmail.com>
Date:   Wed Nov 21 15:15:30 2018 -0500

    Use document.scrollingElement where appropriate (#33)

    Fixes #14

Author: stephenmcgruer

index.html

@@ -11,7 +11,7 @@
   <link href="https://www.w3.org/StyleSheets/TR/2016/W3C-UD" rel="stylesheet" type="text/css">
   <meta content="Bikeshed version 0da7328bb90ef81993146377e4e0fed236969c4c" name="generator">
   <link href="https://wicg.github.io/scroll-animations/" rel="canonical">
-  <meta content="f566763248e1f7651d5c8af5871cf10c717233e7" name="document-revision">
+  <meta content="77803dcc67881b47bb46abbd1a4b34f0d72b431f" name="document-revision">
   <link href="web-animations.css" rel="stylesheet" type="text/css">
 <style>/* style-md-lists */
 
@@ -595,9 +595,7 @@ <h4 class="heading settled" data-level="3.1.2" id="scrolltimeline-interface"><sp
       <dd data-md>
        <p>The scrollable element whose scrolling triggers the activation and drives the
 progress of the timeline.</p>
-       <p>If this is not specified, the document element of the <a data-link-type="dfn" href="https://html.spec.whatwg.org/multipage/browsers.html#active-document" id="ref-for-active-document">active document</a> for the
-current <a data-link-type="dfn" href="https://html.spec.whatwg.org/multipage/browsers.html#browsing-context" id="ref-for-browsing-context">browsing context</a>, as determined at the time the <code class="idl"><a data-link-type="idl" href="#scrolltimeline" id="ref-for-scrolltimeline③">ScrollTimeline</a></code> is
-constructed, is used.</p>
+       <p>If this is not specified, the <code class="idl"><a data-link-type="idl" href="https://drafts.csswg.org/cssom-view-1/#dom-document-scrollingelement" id="ref-for-dom-document-scrollingelement">scrollingElement</a></code> of the <a data-link-type="dfn" href="https://html.spec.whatwg.org/multipage/browsers.html#active-document" id="ref-for-active-document">active document</a> for the current <a data-link-type="dfn" href="https://html.spec.whatwg.org/multipage/browsers.html#browsing-context" id="ref-for-browsing-context">browsing context</a>, as determined at the time the <code class="idl"><a data-link-type="idl" href="#scrolltimeline" id="ref-for-scrolltimeline③">ScrollTimeline</a></code> is constructed, is used.</p>
        <p>Note that the <code class="idl"><a data-link-type="idl" href="#dom-scrolltimeline-scrollsource" id="ref-for-dom-scrolltimeline-scrollsource①">scrollSource</a></code>'s <code class="idl"><a data-link-type="idl" href="https://dom.spec.whatwg.org/#dom-node-ownerdocument" id="ref-for-dom-node-ownerdocument">ownerDocument</a></code> may change over the lifetime
 of the scroll timeline. This does not affect the scroll timeline; the timeline
 continues to be driven by the scroll progress of the <code class="idl"><a data-link-type="idl" href="#dom-scrolltimeline-scrollsource" id="ref-for-dom-scrolltimeline-scrollsource②">scrollSource</a></code>.</p>
@@ -1113,6 +1111,12 @@ <h3 class="no-num no-ref heading settled" id="index-defined-here"><span class="c
     <li><a href="#ref-for-css-layout-box">3.1.4. The current time of a ScrollTimeline</a>
    </ul>
   </aside>
+  <aside class="dfn-panel" data-for="term-for-dom-document-scrollingelement">
+   <a href="https://drafts.csswg.org/cssom-view-1/#dom-document-scrollingelement">https://drafts.csswg.org/cssom-view-1/#dom-document-scrollingelement</a><b>Referenced in:</b>
+   <ul>
+    <li><a href="#ref-for-dom-document-scrollingelement">3.1.2. The ScrollTimeline interface</a>
+   </ul>
+  </aside>
   <aside class="dfn-panel" data-for="term-for-element">
    <a href="https://dom.spec.whatwg.org/#element">https://dom.spec.whatwg.org/#element</a><b>Referenced in:</b>
    <ul>
@@ -1261,6 +1265,7 @@ <h3 class="no-num no-ref heading settled" id="index-defined-elsewhere"><span cla
     <a data-link-type="biblio">[cssom-view-1]</a> defines the following terms:
     <ul>
      <li><span class="dfn-paneled" id="term-for-css-layout-box" style="color:initial">css layout box</span>
+     <li><span class="dfn-paneled" id="term-for-dom-document-scrollingelement" style="color:initial">scrollingElement</span>
     </ul>
    <li>
     <a data-link-type="biblio">[DOM]</a> defines the following terms: