Stop using parts.

lib/src/base64.dart

 // Copyright (c) 2012, 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 crypto;
+library crypto.base64;
+
+import 'dart:convert';
+import 'dart:typed_data';
 
 const Base64Codec BASE64 = const Base64Codec();
 
 const List<int> _decodeTable = const [
   -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -1, -2, -2, -1, -2, -2,
   -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
   -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, 62, -2, 62, -2, 63,
   52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -2, -2, -2,  0, -2, -2,
   -2,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
   15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -2, -2, -2, -2, 63,
@@ skipping 364 matching lines @@
     }
   }
 
   void close() {
     if (_unconverted.isNotEmpty) {
       _outSink.add(_decoder.convert(_unconverted));
     }
     _outSink.close();
   }
 }