Update charted to 0.4.8 and roll

packages/usage/test/web_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 usage.web_test;
 
 import 'dart:async';
+import 'dart:html';
 
 import 'package:test/test.dart';
 import 'package:usage/src/usage_impl_html.dart';
 
 import 'hit_types_test.dart' as hit_types_test;
 import 'usage_impl_test.dart' as usage_impl_test;
 import 'usage_test.dart' as usage_test;
 import 'uuid_test.dart' as uuid_test;
 
 void main() {
   // Define the tests.
   hit_types_test.defineTests();
   usage_test.defineTests();
   usage_impl_test.defineTests();
   uuid_test.defineTests();
 
-  // Define some web specfic tests.
+  // Define some web specific tests.
   defineWebTests();
 }
 
 void defineWebTests() {
   group('HtmlPostHandler', () {
-    test('sendPost', () {
+    test('sendPost', () async {
       MockRequestor client = new MockRequestor();
-      HtmlPostHandler postHandler = new HtmlPostHandler(
-          mockRequestor: client.request);
-      Map args = {'utv': 'varName', 'utt': 123};
-      return postHandler.sendPost('http://www.google.com', args).then((_) {
-        expect(client.sendCount, 1);
-      });
+      HtmlPostHandler postHandler =
+          new HtmlPostHandler(mockRequestor: client.request);
+      Map<String, dynamic> args = {'utv': 'varName', 'utt': 123};
+
+      await postHandler.sendPost('http://www.google.com', args);
+      expect(client.sendCount, 1);
     });
   });
 
   group('HtmlPersistentProperties', () {
     test('add', () {
-      HtmlPersistentProperties props = new HtmlPersistentProperties('foo_props');
+      HtmlPersistentProperties props =
+          new HtmlPersistentProperties('foo_props');
       props['foo'] = 'bar';
       expect(props['foo'], 'bar');
     });
 
     test('remove', () {
-      HtmlPersistentProperties props = new HtmlPersistentProperties('foo_props');
+      HtmlPersistentProperties props =
+          new HtmlPersistentProperties('foo_props');
       props['foo'] = 'bar';
       expect(props['foo'], 'bar');
       props['foo'] = null;
       expect(props['foo'], null);
     });
   });
 }
 
 class MockRequestor {
   int sendCount = 0;
 
-  Future request(String url, {String method, String sendData}) {
+  Future<HttpRequest> request(String url, {String method, sendData}) {
     expect(url, isNotEmpty);
     expect(method, isNotEmpty);
     expect(sendData, isNotEmpty);
 
     sendCount++;
     return new Future.value();
   }
 }