Roll Observatory deps (charted -> ^0.3.0)

packages/usage/lib/src/usage_impl_html.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_impl_html;
 
 import 'dart:async';
 import 'dart:convert' show JSON;
 import 'dart:html';
 
 import 'usage_impl.dart';
 
 class HtmlPostHandler extends PostHandler {
   final Function mockRequestor;
 
   HtmlPostHandler({Function this.mockRequestor});
 
-  Future sendPost(String url, Map<String, String> parameters) {
+  Future sendPost(String url, Map<String, dynamic> parameters) {
     int viewportWidth = document.documentElement.clientWidth;
     int viewportHeight = document.documentElement.clientHeight;
 
     parameters['vp'] = '${viewportWidth}x$viewportHeight';
 
     String data = postEncode(parameters);
     var request = mockRequestor == null ? HttpRequest.request : mockRequestor;
     return request(url, method: 'POST', sendData: data).catchError((e) {
       // Catch errors that can happen during a request, but that we can't do
       // anything about, e.g. a missing internet conenction.
@@ skipping 15 matching lines @@
   void operator[]=(String key, dynamic value) {
     if (value == null) {
       _map.remove(key);
     } else {
       _map[key] = value;
     }
 
     window.localStorage[name] = JSON.encode(_map);
   }
 }