Add toUri and fromUri functions to pathos.

sdk/lib/_internal/dartdoc/test/export_map_test.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.
 
 import 'dart:io';
 
 import 'package:pathos/path.dart' as pathos;
 import 'package:unittest/unittest.dart';
 
 import '../lib/src/export_map.dart';
@@ skipping 355 matching lines @@
     test('merging hide + hide takes the intersection', () {
       expect(new Export('', '', hide: ['x', 'y'])
               .merge(new Export('', '', hide: ['y', 'z'])),
           equals(new Export('', '', hide: ['y'])));
     });
   });
 }
 
 ExportMap parse(List<String> libraries) {
   return new ExportMap.parse(
-      libraries.map(libPath)
-          .map(pathToFileUri),
+      libraries.map(libPath).map(pathos.toUri),
       pathos.join(tempDir, 'packages'));
 }
 
 void createLibrary(String name, [String contents]) {
   if (contents == null) contents = '';
   new Directory(pathos.dirname(libPath(name))).createSync(recursive: true);
   new File(libPath(name)).writeAsStringSync('''
       library ${pathos.basename(name)};
       $contents
   ''');
 }
 
 String libPath(String name) => pathos.normalize(pathos.join(tempDir, name));
 
 void createTempDir() {
   tempDir = new Directory('').createTempSync().path;
   new Directory(pathos.join(tempDir, 'packages')).createSync();
 }
 
 void deleteTempDir() {
   new Directory(tempDir).deleteSync(recursive: true);
 }