Removed fixed dependencies

packages/package_config/lib/packages_file.dart

 // Copyright (c) 2015, 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 package_config.packages_file;
 
 import "package:charcode/ascii.dart";
+
 import "src/util.dart" show isValidPackageName;
 
 /// Parses a `.packages` file into a map from package name to base URI.
 ///
 /// The [source] is the byte content of a `.packages` file, assumed to be
 /// UTF-8 encoded. In practice, all significant parts of the file must be ASCII,
 /// so Latin-1 or Windows-1252 encoding will also work fine.
 ///
 /// If the file content is available as a string, its [String.codeUnits] can
 /// be used as the `source` argument of this function.
@@ skipping 163 matching lines @@
   } else if (index > 0) {
     return new Uri(
         path: '../' * (base.length - index) + target.skip(index).join('/'));
   } else {
     return uri;
   }
 }
 
 // TODO: inline to uri.normalizePath() when we move to 1.11
 Uri _normalizePath(Uri uri) => new Uri().resolveUri(uri);