Roll Observatory deps (charted -> ^0.3.0)

packages/usage/test/hit_types_test.dart

Index: packages/usage/test/hit_types_test.dart
diff --git a/packages/usage/test/hit_types_test.dart b/packages/usage/test/hit_types_test.dart
index 6cfa321bfbd2ab732efd08ab321439fbb5daf650..4bfb608b772815cfc2000789ba6537b5c7966bb2 100644
--- a/packages/usage/test/hit_types_test.dart
+++ b/packages/usage/test/hit_types_test.dart
@@ -6,11 +6,13 @@ library usage.hit_types_test;
 
 import 'dart:async';
 
+import 'package:test/test.dart';
 import 'package:usage/usage.dart';
-import 'package:unittest/unittest.dart';
 
 import 'src/common.dart';
 
+main() => defineTests();
+
 void defineTests() {
   group('screenView', () {
     test('simple', () {
@@ -81,8 +83,6 @@ void defineTests() {
       AnalyticsTimer timer =
           mock.startTimer('compile', category: 'Build', label: 'Compile');
 
-      int time;
-
       return new Future.delayed(new Duration(milliseconds: 20), () {
         return timer.finish().then((_) {
           expect(mock.mockPostHandler.sentValues, isNot(isEmpty));