Update pkg/serialization to use Symbols and synchronous mirrors

pkg/serialization/lib/serialization.dart

 // Copyright (c) 2012, 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.
 
 /**
  * This provides a general-purpose serialization facility for Dart objects. A
  * [Serialization] is defined in terms of [SerializationRule]s and supports
  * reading and writing to different formats.
  *
  * Setup
@@ skipping 301 matching lines @@
   }
 
   /** Set up the default rules, for lists and primitives. */
   void addDefaultRules() {
     addRule(new PrimitiveRule());
     addRule(new ListRule());
     // Both these rules apply to lists, so unless otherwise indicated,
     // it will always find the first one.
     addRule(new ListRuleEssential());
     addRule(new MapRule());
+    addRule(new SymbolRule());
   }
 
   /**
    * Add a new SerializationRule [rule]. The addRuleFor method will probably
    * handle most simple cases, but for adding an arbitrary rule, including
    * a SerializationRule subclass which you have created, you can use this
    * method.
    */
   void addRule(SerializationRule rule) {
     rule.number = _rules.length;
@@ skipping 106 matching lines @@
       ..addRuleFor(new ListRule())
       ..addRuleFor(new MapRule())
       ..addRuleFor(new PrimitiveRule())
       ..addRuleFor(new ListRuleEssential())
       ..addRuleFor(basicRule,
           constructorFields: ['type',
             'constructorName',
             'constructorFields', 'regularFields', []],
           fields: [])
       ..addRule(new NamedObjectRule())
-      ..addRule(new MirrorRule());
+      ..addRule(new MirrorRule())
+      ..addRule(new SymbolRule());
     meta.namedObjects = namedObjects;
     return meta;
   }
 
   /** Return true if our [namedObjects] collection has an entry for [object].*/
   bool _hasNameFor(object) {
     var sentinel = const _Sentinel();
     return _nameFor(object, () => sentinel) != sentinel;
   }
 
@@ skipping 10 matching lines @@
 }
 
 /**
  * An exception class for errors during serialization.
  */
 class SerializationException implements Exception {
   final String message;
   const SerializationException([this.message]);
   toString() => "SerializationException($message)";
 }