Add promises to AnimationPlayer interface

Author: birtles

web-animations/index.html

@@ -5709,6 +5709,22 @@ <h3>The <code>AnimationPlayer</code> interface</h3>
             Setting this attribute follows the procedure to <a>update the player
             playback rate</a> of this object to the new value.
           </dd>
+          <dt>readonly attribute Promise ready</dt>
+          <dd>
+            Returns the <a>current ready promise</a> for this object.
+            <p class="todo">
+              This should be <code>Promise&lt;AnimationPlayer&gt;</code> but
+              this version of respec doesn't support that.
+            </p>
+          </dd>
+          <dt>readonly attribute Promise finished</dt>
+          <dd>
+            Returns the <a>current finished promise</a> for this object.
+            <p class="todo">
+              This should be <code>Promise&lt;AnimationPlayer&gt;</code> but
+              this version of respec doesn't support that.
+            </p>
+          </dd>
           <dt>readonly attribute boolean paused</dt>
           <dd>
             The <a>paused state</a> of this player.