Allow "bulk editing" of the CssStyleDeclaration objects in an ElementList as well

tools/dom/templates/html/impl/impl_Element.darttemplate

 // Copyright (c) 2012, 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.
 
 part of $LIBRARYNAME;
 
 class _ChildrenElementList extends ListBase<Element> {
   // Raw Element.
   final Element _element;
   final HtmlCollection _childElements;
@@ skipping 158 matching lines @@
    *
    *     htmlList.classes.add('selected');
    *     htmlList.classes.toggle('isOnline');
    *     htmlList.classes.remove('selected');
    */
   CssClassSet get classes;
 
   /** Replace the classes with `value` for every element in this list. */
   set classes(Iterable<String> value);
 
+  /** The union of all styles associated with the [Element]s in this list. */
+  CssStyleDeclarationSet get style;
+
   /** 
    * Access dimensions and position of the Elements in this list.
    * 
    * Setting the height or width properties will set the height or width
    * property for all elements in the list. This returns a rectangle with the 
    * dimenions actually available for content
    * in this element, in pixels, regardless of this element's box-sizing 
    * property. Getting the height or width returns the height or width of the
    * first Element in this list. 
    *
@@ skipping 75 matching lines @@
   }
 
   Element get first => _nodeList.first;
 
   Element get last => _nodeList.last;
 
   Element get single => _nodeList.single;
 
   CssClassSet get classes => new _MultiElementCssClassSet(_elementList);
 
+  CssStyleDeclarationSet get style => 
+      new CssStyleDeclarationSet._(_elementList);
+
   void set classes(Iterable<String> value) {
     _elementList.forEach((e) => e.classes = value);
   }
 
   CssRect get contentEdge => new _ContentCssListRect(_elementList);
   
   CssRect get paddingEdge => _elementList.first.paddingEdge;
 
   CssRect get borderEdge => _elementList.first.borderEdge;
 
@@ skipping 986 matching lines @@
   const ScrollAlignment._internal(this._value);
   toString() => 'ScrollAlignment.$_value';
 
   /// Attempt to align the element to the top of the scrollable area.
   static const TOP = const ScrollAlignment._internal('TOP');
   /// Attempt to center the element in the scrollable area.
   static const CENTER = const ScrollAlignment._internal('CENTER');
   /// Attempt to align the element to the bottom of the scrollable area.
   static const BOTTOM = const ScrollAlignment._internal('BOTTOM');
 }