Fixing comment constructor not functioning on IE

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

Index: tools/dom/templates/html/impl/impl_Comment.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_WebKitCSSKeyframesRule.darttemplate b/tools/dom/templates/html/impl/impl_Comment.darttemplate
similarity index 65%
copy from tools/dom/templates/html/impl/impl_WebKitCSSKeyframesRule.darttemplate
copy to tools/dom/templates/html/impl/impl_Comment.darttemplate
index a0c7f902fbc4b2654325781a89f85910067bec31..df0d378efc2fcef080fd9854b8a8e80ec3b35ef2 100644
--- a/tools/dom/templates/html/impl/impl_WebKitCSSKeyframesRule.darttemplate
+++ b/tools/dom/templates/html/impl/impl_Comment.darttemplate
@@ -6,15 +6,12 @@ part of $LIBRARYNAME;
 
 @DocsEditable()
 $(ANNOTATIONS)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$MIXINS$IMPLEMENTS$NATIVESPEC {
-$!MEMBERS
-
 $if DART2JS
-  void appendRule(String rule) {
-    if (JS('bool', '("appendRule" in #)', this)) {
-      JS('', '#.appendRule(#)', this, rule);
-    } else {
-      JS('', '#.insertRule(#)', this, rule);
+  factory Comment([String data]) {
+    if (data != null) {
+      return JS('Comment', '#.createComment(#)', document, data);
     }
+    return JS('Comment', '#.createComment("")', document);
   }
 $endif
-}
+$!MEMBERS}