Revert "Adding Element.AddHTML and Element.addText methods."

lib/html/doc/interface/Element.dartdoc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // WARNING:
 //   This file contains documentation that is merged into the real source.
 //   Do not make code changes here.
 
 interface ElementList extends List<Element> {
   // TODO(jacobr): add element batch manipulation methods.
@@ skipping 67 matching lines @@
   /** @domName Window.getComputedStyle */
   Future<CSSStyleDeclaration> get computedStyle();
 
   /** @domName Window.getComputedStyle */
   Future<CSSStyleDeclaration> getComputedStyle(String pseudoElement);
 
   Element clone(bool deep);
 
   Element get parent();
 
-  void addText(String text) {
-    this.insertAdjacentText('beforeend', text);
-  }
-
-  void addHTML(String text) {
-    this.insertAdjacentHTML('beforeend', text);
-  }
-
 
   /**
    * @domName EventTarget.addEventListener, EventTarget.removeEventListener, EventTarget.dispatchEvent
    */
   ElementEvents get on();
 
   static final int ALLOW_KEYBOARD_INPUT = 1;
 
   /** @domName Element.childElementCount */
   final int $dom_childElementCount;
@@ skipping 268 matching lines @@
   EventListenerList get touchEnter();
 
   EventListenerList get touchLeave();
 
   EventListenerList get touchMove();
 
   EventListenerList get touchStart();
 
   EventListenerList get transitionEnd();
 }