use symbol literals instead of const ctor in packages

pkg/polymer/lib/src/instance.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.
 
 part of polymer;
 
 /**
  * Use this annotation to publish a field as an attribute. For example:
  *
  *     class MyPlaybackElement extends PolymerElement {
@@ skipping 316 matching lines @@
   // TODO(jmesserly): this should probably take a ClassMirror instead of
   // TypeMirror, but it is currently impossible to get from a TypeMirror to a
   // ClassMirror.
   Object deserializeValue(String value, Object defaultValue, TypeMirror type) =>
       deserialize.deserializeValue(value, defaultValue, type);
 
   String serializeValue(Object value, TypeMirror inferredType) {
     if (value == null) return null;
 
     final type = inferredType.qualifiedName;
-    if (type == const Symbol('dart.core.bool')) {
+    if (type == #dart.core.bool) {
       return _toBoolean(value) ? '' : null;
-    } else if (type == const Symbol('dart.core.String')
-        || type == const Symbol('dart.core.int')
-        || type == const Symbol('dart.core.double')) {
+    } else if (type == #dart.core.String
+        || type == #dart.core.int
+        || type == #dart.core.double) {
       return '$value';
     }
     return null;
   }
 
   void reflectPropertyToAttribute(String name) {
     // TODO(sjmiles): consider memoizing this
     final self = reflect(this);
     // try to intelligently serialize property value
     // TODO(jmesserly): cache symbol?
     final propValue = self.getField(new Symbol(name)).reflectee;
     final property = _declaration._publish[name];
     var inferredType = _inferPropertyType(propValue, property);
     final serializedValue = serializeValue(propValue, inferredType);
     // boolean properties must reflect as boolean attributes
     if (serializedValue != null) {
       attributes[name] = serializedValue;
       // TODO(sorvell): we should remove attr for all properties
       // that have undefined serialization; however, we will need to
       // refine the attr reflection system to achieve this; pica, for example,
       // relies on having inferredType object properties not removed as
       // attrs.
-    } else if (inferredType.qualifiedName == const Symbol('dart.core.bool')) {
+    } else if (inferredType.qualifiedName == #dart.core.bool) {
       attributes.remove(name);
     }
   }
 
   /**
    * Creates the document fragment to use for each instance of the custom
    * element, given the `<template>` node. By default this is equivalent to:
    *
    *     template.createInstance(this, polymerSyntax);
    *
@@ skipping 528 matching lines @@
 
 bool _toBoolean(value) => null != value && false != value;
 
 TypeMirror _propertyType(DeclarationMirror property) =>
     property is VariableMirror
         ? (property as VariableMirror).type
         : (property as MethodMirror).returnType;
 
 TypeMirror _inferPropertyType(Object value, DeclarationMirror property) {
   var type = _propertyType(property);
-  if (type.qualifiedName == const Symbol('dart.core.Object') ||
-      type.qualifiedName == const Symbol('dynamic')) {
+  if (type.qualifiedName == #dart.core.Object ||
+      type.qualifiedName == #dynamic) {
     // Attempt to infer field type from the default value.
     if (value != null) {
       type = reflect(value).type;
     }
   }
   return type;
 }
 
 final Logger _observeLog = new Logger('polymer.observe');
 final Logger _eventsLog = new Logger('polymer.events');
 final Logger _unbindLog = new Logger('polymer.unbind');
 final Logger _bindLog = new Logger('polymer.bind');
 
 final Expando _shadowHost = new Expando<Element>();
 
 final Expando _eventHandledTable = new Expando<Set<Node>>();