[web-animations-1] Drop step to clear pending tasks when setting a null effect

This closes w3c#2077.

Author: birtles

web-animations-1/Overview.bs

@@ -809,9 +809,6 @@ follows:
     <var>animation</var>, if any.
 1.  If <var>new effect</var> is the same object as <var>old effect</var>,
     abort this procedure.
-1.  If <var>new effect</var> is null and <var>old effect</var> is not null,
-    run the procedure to <a>reset an animation's pending tasks</a> on
-    <var>animation</var>.
 1.  If <var>animation</var> has a <a>pending pause task</a>, reschedule that
     task to run as soon as <var>animation</var> is <a>ready</a>.
 1.  If <var>animation</var> has a <a>pending play task</a>, reschedule that task
@@ -5924,6 +5921,9 @@ The following changes have been made since the <a
 *   Dropped global clock definition and added the [=update animations
     and send events=] procedure so that the updating of animations can be
     integrated with HTML's [=update the rendering=] procedure.
+*   Removed step to reset pending tasks when a null effect it set on an
+    animation
+    (<a href="https://github.com/w3c/csswg-drafts/issues/2077">#2077</a>).
 *   Clarified that the [=pending play task=] and [=pending pause task=] must be
     run asynchronously.
 *   Fixed a mistake in the calculation of the <a>hold time</a> when an pause