Make common file mode and encoding constants available on the top level in dart:io

sdk/lib/io/string_transformer.dart

 // Copyright (c) 2013, 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.
 
 part of dart.io;
 
 /**
  * String encodings.
  */
 class Encoding {
   static const Encoding UTF_8 = const Encoding._internal("utf-8");
   static const Encoding ISO_8859_1 = const Encoding._internal("iso-8859-1");
   static const Encoding ASCII = const Encoding._internal("us-ascii");
 
+  /**
+   * SYSTEM encoding is the current code page on Windows and UTF-8 on
+   * Linux and Mac.
+   */
+  static const Encoding SYSTEM = const Encoding._internal("system");
+
   // All aliasses (in lowercase) of supported encoding from
   // http://www.iana.org/assignments/character-sets/character-sets.xml.
   static Map<String, Encoding> _nameToEncoding = <String, Encoding> {
     // ISO_8859-1:1987.
     "iso_8859-1:1987": ISO_8859_1,
     "iso-ir-100": ISO_8859_1,
     "iso_8859-1": ISO_8859_1,
     "iso-8859-1": ISO_8859_1,
     "latin1": ISO_8859_1,
     "l1": ISO_8859_1,
@@ skipping 35 matching lines @@
     return _nameToEncoding[name];
   }
 
   /**
    * Name of the encoding. This will be the lower-case version of one of the
    * IANA official names for the character set (see
    * http://www.iana.org/assignments/character-sets/character-sets.xml)
    */
   final String name;
 
-  /**
-   * SYSTEM encoding is the current code page on Windows and UTF-8 on
-   * Linux and Mac.
-   */
-  static const Encoding SYSTEM = const Encoding._internal("system");
   const Encoding._internal(String this.name);
 }
 
+const UTF_8 = Encoding.UTF_8;
+const ISO_8859_1 = Encoding.ISO_8859_1;
+const ASCII = Encoding.ASCII;
 
 /**
  * Stream transformer that can decode a stream of bytes into a stream of
  * strings using [encoding].
  *
  * Invalid or forbidden byte-sequences will not produce errors, but will instead
  * insert [replacementChar] in the decoded strings.
  */
 class StringDecoder implements StreamTransformer<List<int>, String> {
   var _decoder;
@@ skipping 273 matching lines @@
 
 // Utility class for decoding Windows current code page data delivered
 // as a stream of bytes.
 class _WindowsCodePageDecoder extends StreamEventTransformer<List<int>, String> {
   void handleData(List<int> data, EventSink<String> sink) {
     sink.add(_decodeBytes(data));
   }
 
   external static String _decodeBytes(List<int> bytes);
 }