Fix SVGElement#classes.

client/html/release/htmlimpl.dart

Index: client/html/release/htmlimpl.dart
diff --git a/client/html/release/htmlimpl.dart b/client/html/release/htmlimpl.dart
index 38b83b901afdcec2c2fdbf7c253dd63000a73038..e61ae76213b39a7fd6dc425c8293d5ca86b62db5 100644
--- a/client/html/release/htmlimpl.dart
+++ b/client/html/release/htmlimpl.dart
@@ -18660,7 +18660,7 @@ class _CssClassSet implements Set<String> {
   Set<String> _read() {
     // TODO(mattsh) simplify this once split can take regex.
     Set<String> s = new Set<String>();
-    for (String name in _element.className.split(' ')) {
+    for (String name in _className().split(' ')) {
       String trimmed = name.trim();
       if (!trimmed.isEmpty()) {
         s.add(trimmed);
@@ -18670,6 +18670,12 @@ class _CssClassSet implements Set<String> {
   }
 
   /**
+   * Read the class names as a space-separated string. This is meant to be
+   * overridden by subclasses.
+   */
+  String _className() => _element.className;
+
+  /**
    * Join all the elements of a set into one string and write
    * back to the element.
    */
@@ -24040,6 +24046,16 @@ class SVGDocumentWrappingImplementation extends DocumentWrappingImplementation i
 // 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.
 
+class _SVGClassSet extends _CssClassSet {
+  _SVGClassSet(element) : super(element);
+
+  String _className() => _element.className.baseVal;
+
+  viod _write(Set s) {
+    _element.className.baseVal = _formatSet(s);
+  }
+}
+
 class SVGElementWrappingImplementation extends ElementWrappingImplementation implements SVGElement {
   SVGElementWrappingImplementation._wrap(ptr) : super._wrap(ptr) {}
 
@@ -24063,6 +24079,13 @@ class SVGElementWrappingImplementation extends ElementWrappingImplementation imp
         'top-level elements but 1 expected');
   }
 
+  Set<String> get classes() {
+    if (_cssClassSet === null) {
+      _cssClassSet = new _SVGClassSet(_ptr);
+    }
+    return _cssClassSet;
+  }
+
   String get id() { return _ptr.id; }
 
   void set id(String value) { _ptr.id = value; }