Roll Observatory deps (charted -> ^0.3.0)

packages/usage/test/usage_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.
 
 library usage.usage_test;
 
-import 'package:unittest/unittest.dart';
+import 'package:test/test.dart';
 import 'package:usage/usage.dart';
 
+main() => defineTests();
+
 void defineTests() {
   group('AnalyticsMock', () {
     test('simple', () {
       AnalyticsMock mock = new AnalyticsMock();
       mock.sendScreenView('main');
       mock.sendEvent('files', 'save');
       mock.sendSocial('g+', 'plus', 'userid');
       mock.sendTiming('compile', 123);
       mock.startTimer('compile').finish();
       mock.sendException('FooException');
@@ skipping 32 matching lines @@
     });
 
     test('shorten 3', () {
       expect(sanitizeStacktrace(
           'foo (package:foo/foo.dart:3:13)\n'
           'bar (dart:async/schedule_microtask.dart:41)'),
           'foo (foo/foo.dart:3:13) bar (async/schedule_microtask.dart:41)');
     });
   });
 }