Sync the HTMLTableElement return types with the spec

third_party/WebKit/Source/core/html/HTMLTableElement.idl

 /*
  * Copyright (C) 2006, 2007, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
  *
  * 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.
  */
 
 // https://html.spec.whatwg.org/#the-table-element
 
 interface HTMLTableElement : HTMLElement {
     // TODO(philipj): The caption, tHead and tFoot setters should never throw.
     [RaisesException=Setter, LegacyInterfaceTypeChecking] attribute HTMLTableCaptionElement? caption;
-    HTMLElement createCaption();
+    HTMLTableCaptionElement createCaption();
     void deleteCaption();
     [RaisesException=Setter, LegacyInterfaceTypeChecking] attribute HTMLTableSectionElement? tHead;
-    HTMLElement createTHead();
+    HTMLTableSectionElement createTHead();
     void deleteTHead();
     [RaisesException=Setter, LegacyInterfaceTypeChecking] attribute HTMLTableSectionElement? tFoot;
-    HTMLElement createTFoot();
+    HTMLTableSectionElement createTFoot();
     void deleteTFoot();
     readonly attribute HTMLCollection tBodies;
-    HTMLElement createTBody();
+    HTMLTableSectionElement createTBody();
     readonly attribute HTMLCollection rows;
-    [RaisesException] HTMLElement insertRow(optional long index = -1);
+    [RaisesException] HTMLTableRowElement insertRow(optional long index = -1);
     [RaisesException] void deleteRow(long index);
     // attribute boolean sortable;
     // void stopSorting();
 
     // obsolete members
     // https://html.spec.whatwg.org/#HTMLTableElement-partial
     [Reflect] attribute DOMString align;
     [Reflect] attribute DOMString border;
     [Reflect] attribute DOMString frame;
     [Reflect] attribute DOMString rules;
     [Reflect] attribute DOMString summary;
     [Reflect] attribute DOMString width;
 
     [Reflect, TreatNullAs=EmptyString] attribute DOMString bgColor;
     [Reflect, TreatNullAs=EmptyString] attribute DOMString cellPadding;
     [Reflect, TreatNullAs=EmptyString] attribute DOMString cellSpacing;
 };