Update charted to 0.4.8 and roll

packages/yaml/lib/src/parser.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 yaml.parser;
-
 import 'package:source_span/source_span.dart';
 import 'package:string_scanner/string_scanner.dart';
 
 import 'event.dart';
 import 'scanner.dart';
 import 'style.dart';
 import 'token.dart';
 import 'utils.dart';
 import 'yaml_document.dart';
 import 'yaml_exception.dart';
@@ skipping 645 matching lines @@
   }
 
   /// Generate an empty scalar event.
   Event _processEmptyScalar(SourceLocation location) =>
       new ScalarEvent(location.pointSpan(), '', ScalarStyle.PLAIN);
 
   /// Parses directives.
   Pair<VersionDirective, List<TagDirective>> _processDirectives() {
     var token = _scanner.peek();
 
-    var versionDirective;
+    VersionDirective versionDirective;
     var tagDirectives = <TagDirective>[];
     while (token.type == TokenType.VERSION_DIRECTIVE ||
            token.type == TokenType.TAG_DIRECTIVE) {
       if (token is VersionDirectiveToken) {
         if (versionDirective != null) {
           throw new YamlException("Duplicate %YAML directive.", token.span);
         }
 
         if (token.major != 1 || token.minor == 0) {
           throw new YamlException(
@@ skipping 124 matching lines @@
 
   /// Expect nothing.
   static const END = const _State("END");
 
   final String name;
 
   const _State(this.name);
 
   String toString() => name;
 }