Refined types for most HtmlElement factory constructors

tools/dom/scripts/css_code_generator.py

 #!/usr/bin/python
 #
 # Copyright (c) 2014, 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.
 
 """Generates CSSStyleDeclaration template file from css property definitions
 defined in WebKit."""
 
 import tempfile, os, re
@@ skipping 89 matching lines @@
 part of $LIBRARYNAME;
 """ % SOURCE_PATH)
 
 
   class_file.write("""
 $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME $EXTENDS with
     $(CLASSNAME)Base $IMPLEMENTS {
   factory $CLASSNAME() => new CssStyleDeclaration.css('');
 
   factory $CLASSNAME.css(String css) {
-    final style = new Element.tag('div').style;
+    final style = new DivElement().style;
     style.cssText = css;
     return style;
   }
 
   /// Returns the value of the property if the provided *CSS* property
   /// name is supported on this element and if the value is set. Otherwise
   /// returns an empty string.
   ///
   /// Please note the property name uses camelCase, not-hyphens.
   String getPropertyValue(String propertyName) {
@@ skipping 238 matching lines @@
       class_lines.append(annotated[base_css_name])
     class_lines.append("""
   set %s(String value) {
     setProperty('%s', value, '');
   }
 """ % (camel_case_name, css_name))
 
   class_file.write(''.join(class_lines));
   class_file.write('}\n')
   class_file.close()