Update locale char when moving position in number parsing in the JSON parser.

lib/json/json.dart

 // Copyright (c) 2011, 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("json");
 
 // Pure Dart implementation of JSON protocol.
 
 /**
  * Utility class to parse JSON and serialize objects to JSON.
@@ skipping 286 matching lines @@
         char = _nextChar();
         isInt = false;
         while (_isDigit(char)) char = _nextChar();
       } else {
         _error('Expected digit following comma');
       }
     }
 
     if (char === CHAR_E || char === CHAR_CAPITAL_E) {
       char = _nextChar();
-      if (char === MINUS || char === PLUS) position++;
+      if (char === MINUS || char === PLUS) char = _nextChar();
       if (_isDigit(char)) {
         char = _nextChar();
         isInt = false;
         while (_isDigit(char)) char = _nextChar();
       } else {
         _error('Expected digit following \'e\' or \'E\'');
       }
     }
 
     String number = json.substring(startPos, position);
@@ skipping 202 matching lines @@
         });
         _sb.add('}');
         _seen.removeLast();
         return;
 
       default:
         throw const JsonUnsupportedObjectType();
     }
   }
 }