Fix issues that broke editing on browsers without Shadow DOM support.

dart/site/try/src/decoration.dart

 // Copyright (c) 2013, 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.
 
 library trydart.decoration;
 
 import 'dart:html';
 
 import 'shadow_root.dart' show
     setShadowRoot;
 
+import 'editor.dart' show
+    diagnostic;
+
 class Decoration {
   final String color;
   final bool bold;
   final bool italic;
   final bool stress;
   final bool important;
 
   const Decoration({this.color: '#000000',
                     this.bold: false,
                     this.italic: false,
@@ skipping 36 matching lines @@
               important: important);
 
   Element applyTo(text) {
     var element = super.applyTo(text);
     var nodes = new List.from(element.nodes);
     element.nodes.clear();
     var tip = new Text('');
     if (kind == 'error') {
       tip = error(message);
     }
-    return element..append(
-        new AnchorElement()
-            ..classes.add('diagnostic')
-            ..nodes.addAll(nodes)
-            ..append(tip));
+    return element..append(diagnostic(nodes, tip));
   }
 }
 
 createAlert(text, [String cls]) {
   var classes = ['alert'];
   if (cls != null) {
     classes.add(cls);
   }
   SpanElement result = new SpanElement()
       ..classes.addAll(classes)
@@ skipping 29 matching lines @@
 
   Element applyTo(text) {
     var codeCompletion = new DivElement()
         ..contentEditable = 'false'
         ..classes.add('dart-code-completion');
     return super.applyTo(text)
         ..classes.add('dart-code-completion-holder')
         ..nodes.add(codeCompletion);
   }
 }