Implement HTMLMarqueeElement's animation in private scripts

Source/core/html/HTMLMarqueeElement.idl

 /*
  * Copyright (C) 2007 Apple Inc. All rights reserved
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 interface HTMLMarqueeElement : HTMLElement {
-    void start();
-    void stop();
+    [ImplementedInPrivateScript] void start();
+    [ImplementedInPrivateScript] void stop();
 
     [ImplementedInPrivateScript, Reflect] attribute DOMString behavior;
     [ImplementedInPrivateScript, Reflect] attribute DOMString bgColor;
     [ImplementedInPrivateScript, Reflect] attribute DOMString direction;
     [ImplementedInPrivateScript, Reflect] attribute DOMString height;
     [ImplementedInPrivateScript, Reflect] attribute unsigned long hspace;
     [ImplementedInPrivateScript] attribute long loop;
     [ImplementedInPrivateScript] attribute long scrollAmount;
     [ImplementedInPrivateScript] attribute long scrollDelay;
     [ImplementedInPrivateScript, Reflect] attribute boolean trueSpeed;
     [ImplementedInPrivateScript, Reflect] attribute unsigned long vspace;
     [ImplementedInPrivateScript, Reflect] attribute DOMString width;
 
+    [ImplementedInPrivateScript, OnlyExposedToPrivateScript] void createdCallback();
+    [ImplementedInPrivateScript, OnlyExposedToPrivateScript] void attachedCallback();
+    [ImplementedInPrivateScript, OnlyExposedToPrivateScript] void detachedCallback();
+    [ImplementedInPrivateScript, OnlyExposedToPrivateScript] void attributeChangedCallback(DOMString name, DOMString oldValue, DOMString newValue);
+
     // FIXME: Implement the following event handler attributes
     // https://bugs.webkit.org/show_bug.cgi?id=49788
     // attribute EventHandler onbounce;
     // attribute EventHandler onfinish;
     // attribute EventHandler onstart;
 };