Restore workaround for old Chrome bug that also affects Safari and in some cases Firefox, fix test …

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>
     implements NodeListWrapper {
   // Raw Element.
   final Element _element;
@@ skipping 1310 matching lines @@
       }
       treeSanitizer = _defaultSanitizer;
     } else if (validator != null) {
       throw new ArgumentError(
           'validator can only be passed if treeSanitizer is null');
     }
 
     if (_parseDocument == null) {
       _parseDocument = document.implementation.createHtmlDocument('');
       _parseRange = _parseDocument.createRange();
+        
+      // Workaround for Safari bug. Was also previously Chrome bug 229142
+      // - URIs are not resolved in new doc.    
+      var base = _parseDocument.createElement('base');  
+      base.href = document.baseUri;     
+      _parseDocument.head.append(base);
     }
     var contextElement;
     if (this is BodyElement) {
       contextElement = _parseDocument.body;
     } else {
       contextElement = _parseDocument.createElement(tagName);
       _parseDocument.body.append(contextElement);
     }
     var fragment;
     if (Range.supportsCreateContextualFragment &&
@@ skipping 333 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');
 }