Make Source.getDirectory synchronous.

lib/src/source/path.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.
 
 library pub.source.path;
 
 import 'dart:async';
 
 import 'package:path/path.dart' as p;
 
@@ skipping 39 matching lines @@
   }
 
   Future get(PackageId id, String symlink) {
     return new Future.sync(() {
       var dir = _validatePath(id.name, id.description);
       createPackageSymlink(id.name, dir, symlink,
           relative: id.description["relative"]);
     });
   }
 
-  Future<String> getDirectory(PackageId id) =>
-      newFuture(() => _validatePath(id.name, id.description));
+  String getDirectory(PackageId id) => _validatePath(id.name, id.description);
 
   /// Parses a path dependency.
   ///
   /// This takes in a path string and returns a map. The "path" key will be the
   /// original path but resolved relative to the containing path. The
   /// "relative" key will be `true` if the original path was relative.
   ///
   /// A path coming from a pubspec is a simple string. From a lock file, it's
   /// an expanded {"path": ..., "relative": ...} map.
   dynamic parseDescription(String containingPath, description,
@@ skipping 79 matching lines @@
 
     if (fileExists(dir)) {
       fail('Path dependency for package $name must refer to a directory, '
            'not a file. Was "$dir".');
     }
 
     throw new PackageNotFoundException(
         'Could not find package $name at "$dir".');
   }
 }