Update charted to 0.4.8 and roll

packages/yaml/lib/src/scanner.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.scanner;
-
 import 'package:collection/collection.dart';
 import 'package:string_scanner/string_scanner.dart';
 import 'package:source_span/source_span.dart';
 
 import 'style.dart';
 import 'token.dart';
 import 'utils.dart';
 import 'yaml_exception.dart';
 
 /// A scanner that reads a string of Unicode characters and emits [Token]s.
@@ skipping 302 matching lines @@
     if (!_tokenAvailable) _fetchMoreTokens();
     return _tokens.first;
   }
 
   /// Ensures that [_tokens] contains at least one token which can be returned.
   void _fetchMoreTokens() {
     while (true) {
       if (_tokens.isNotEmpty) {
         _staleSimpleKeys();
 
+        // If there are no more tokens to fetch, break.
+        if (_tokens.last.type == TokenType.STREAM_END) break;
+
         // If the current token could be a simple key, we need to scan more
         // tokens until we determine whether it is or not. Otherwise we might
         // not emit the `KEY` token before we emit the value of the key.
         if (!_simpleKeys.any((key) =>
             key != null && key.tokenNumber == _tokensParsed)) {
           break;
         }
       }
 
       _fetchNextToken();
@@ skipping 116 matching lines @@
         } else {
           _fetchValue();
         }
         return;
       default:
         if (!_isNonBreak) _invalidScalarCharacter();
 
         _fetchPlainScalar();
         return;
     }
-
-    throw 'Inaccessible';
   }
 
   /// Throws an error about a disallowed character.
   void _invalidScalarCharacter() =>
       _scanner.error("Unexpected character.", length: 1);
 
   /// Checks the list of potential simple keys and remove the positions that
   /// cannot contain simple keys anymore.
   void _staleSimpleKeys() {
     for (var i = 0; i < _simpleKeys.length; i++) {
@@ skipping 1198 matching lines @@
 
   /// All trailing whitespace is preserved.
   static const KEEP = const _Chomping("KEEP");
 
   final String name;
 
   const _Chomping(this.name);
 
   String toString() => name;
 }