Optimize dartium dart:html bindings so real world application performance is acceptable. Improves d…

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 128 matching lines @@
    *
    * The tag should be a valid SVG element tag name.
    */
   static bool isTagSupported(String tag) {
     var e = new $CLASSNAME.tag(tag);
     return e is $CLASSNAME && !(e is UnknownElement);
   }
 
 $if JSINTEROP
   set _svgClassName(AnimatedString value) =>
-      _blink.BlinkSVGElement.instance.className_Setter_(unwrap_jso(this), unwrap_jso(value));
+      _blink.BlinkSVGElement.instance.className_Setter_(this, value);
 
-  String get className => _svgClassName.baseVal;
-
-  // Unbelievable hack. We can't create an SvgAnimatedString, but we can get
-  // the existing one and change its baseVal. Then we call the blink setter directly
-  // TODO(alanknight): Handle suppressing the SVGAnimated<*> better
-  set className(String s) {
-    var oldClass = _svgClassName;
-    oldClass.baseVal = s;
-    _svgClassName = oldClass;
-  }
 $endif
 $!MEMBERS
 }