Add the NonElementParentNode interface

Source/core/dom/Document.idl

Index: Source/core/dom/Document.idl
diff --git a/Source/core/dom/Document.idl b/Source/core/dom/Document.idl
index f73961540029c56148bb6146aa1894c162171fb6..9bd22f4bb496f43d121043e4775809a60b33aa4f 100644
--- a/Source/core/dom/Document.idl
+++ b/Source/core/dom/Document.idl
@@ -83,10 +83,6 @@ enum VisibilityState { "hidden", "visible", "prerender", "unloaded" };
     [RaisesException=Setter, MeasureAs=DocumentXMLVersion] attribute DOMString? xmlVersion;
     [RaisesException=Setter, MeasureAs=DocumentXMLStandalone] attribute boolean xmlStandalone;
 
-    // https://dom.spec.whatwg.org/#interface-nonelementparentnode
-
-    [PerWorldBindings] Element? getElementById(DOMString elementId);
-
     // https://html.spec.whatwg.org/#the-document-object
 
     // resource metadata management
@@ -228,3 +224,4 @@ enum VisibilityState { "hidden", "visible", "prerender", "unloaded" };
 
 Document implements GlobalEventHandlers;
 Document implements ParentNode;
+Document implements NonElementParentNode;