Implement HTMLMarqueeElement's animation in private scripts

Source/core/html/HTMLMarqueeElement.idl

Index: Source/core/html/HTMLMarqueeElement.idl
diff --git a/Source/core/html/HTMLMarqueeElement.idl b/Source/core/html/HTMLMarqueeElement.idl
index 19841be88df72acee661ed29820d9f025b304e36..bc21290aa9184c77cbc2b6396f8fe574b23e8987 100644
--- a/Source/core/html/HTMLMarqueeElement.idl
+++ b/Source/core/html/HTMLMarqueeElement.idl
@@ -18,8 +18,8 @@
  */
 
 interface HTMLMarqueeElement : HTMLElement {
-    void start();
-    void stop();
+    [ImplementedInPrivateScript] void start();
+    [ImplementedInPrivateScript] void stop();
 
     [ImplementedInPrivateScript, Reflect] attribute DOMString behavior;
     [ImplementedInPrivateScript, Reflect] attribute DOMString bgColor;
@@ -33,6 +33,11 @@ interface HTMLMarqueeElement : HTMLElement {
     [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;