First cut at behaviors. This just implements the lifecycle methodsportion. We may get the rest for …

test/src/common/polymer_descriptor_test.dart

 // Copyright (c) 2014, 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.
 @TestOn('browser')
 library polymer.test.src.common.polymer_descriptor_test;
 
 import 'dart:js';
 import 'package:test/test.dart';
 import 'package:polymer/polymer.dart';
 import 'package:polymer/src/common/polymer_descriptor.dart';
@@ skipping 39 matching lines @@
     var listeners = descriptor['listeners'];
     expect(listeners['tap'], 'onTap');
     expect(listeners['someId.tap'], 'onSomeIdTap');
 
     expect(descriptor['ready'] is JsFunction, isTrue);
     expect(descriptor['attached'] is JsFunction, isTrue);
     expect(descriptor['detached'] is JsFunction, isTrue);
     expect(descriptor['handleSomeEvent'] is JsFunction, isTrue);
     expect(descriptor['myDoubleChanged'] is JsFunction, isTrue);
     expect(descriptor['myNumsCombined'] is JsFunction, isTrue);
+
+    expect(descriptor['behaviors'], isNotNull);
+    expect(descriptor['behaviors'].length, 2);
+    expect(descriptor['behaviors'][0], context['Foo']['BehaviorOne']);
+    expect(descriptor['behaviors'][1], context['Foo']['BehaviorTwo']);
   });
 }
 
+@BehaviorProxy(const ['Foo', 'BehaviorOne'])
+class BehaviorOne {}
+
+@BehaviorProxy(const ['Foo', 'BehaviorTwo'])
+class BehaviorTwo {}
+
 @jsProxyReflectable
-class Test {
+class Test extends Object with BehaviorOne, BehaviorTwo {
   @property
   String myString;
   @Property(notify: true)
   int myInt;
   @Property(observer: 'myDoubleChanged')
   double myDouble;
   @Property(reflectToAttribute: true)
   num myNum;
   @property
   bool myBool;
@@ skipping 53 matching lines @@
   expectEqual(actual, expected);
 }
 
 void expectEqual(JsObject actual, Map expected) {
   expect(actual, isNotNull);
   var keys = context['Object'].callMethod('keys', [actual]);
   for (var key in keys) {
     expect(actual[key], equals(expected[key]));
   }
 }