Refined types for most HtmlElement factory constructors

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

 // 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.
 
 part of $LIBRARYNAME;
 
 class _AttributeClassSet extends CssClassSetImpl {
   final Element _element;
 
   _AttributeClassSet(this._element);
@@ skipping 47 matching lines @@
 
   List<Element> get children => new FilteredElementList(this);
 
   set children(List<Element> value) {
     final children = this.children;
     children.clear();
     children.addAll(value);
   }
 
   String get outerHtml {
-    final container = new Element.tag("div");
+    final container = new DivElement();
     final SvgElement cloned = this.clone(true);
     container.children.add(cloned);
     return container.innerHtml;
   }
 
   String get innerHtml {
-    final container = new Element.tag("div");
+    final container = new DivElement();
     final SvgElement cloned = this.clone(true);
     container.children.addAll(cloned.children);
     return container.innerHtml;
   }
 
   set innerHtml(String value) {
     this.setInnerHtml(value);
   }
 
   DocumentFragment createFragment(String svg,
@@ skipping 58 matching lines @@
     return e is $CLASSNAME && !(e is UnknownElement);
   }
 
 $if JSINTEROP
   set _svgClassName(AnimatedString value) =>
       _blink.BlinkSVGElement.instance.className_Setter_(this, value);
 
 $endif
 $!MEMBERS
 }