Refactor Source and SourceRegistry.

test/package_list_files_test.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.
 
 import 'package:path/path.dart' as p;
 import 'package:pub/src/entrypoint.dart';
 import 'package:pub/src/io.dart';
 import 'package:pub/src/system_cache.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 
@@ skipping 131 matching lines @@
     });
 
     commonTests();
   });
 }
 
 void scheduleEntrypoint([String path]) {
   if (path == null) path = appPath;
   schedule(() {
     root = p.join(sandboxDir, path);
-    entrypoint = new Entrypoint(root,
-        new SystemCache.withSources(rootDir: root));
+    entrypoint = new Entrypoint(root, new SystemCache(rootDir: root));
   }, 'initializing entrypoint at $path');
 
   currentSchedule.onComplete.schedule(() {
     entrypoint = null;
   }, 'nulling entrypoint');
 }
 
 void commonTests() {
   integration('ignores broken symlinks', () {
     // Windows requires us to symlink to a directory that actually exists.
@@ skipping 93 matching lines @@
             unorderedEquals([
           p.join(root, 'packages', 'subfile1.txt'),
           p.join(root, 'packages', 'subfile2.txt'),
           p.join(root, 'packages', 'subsubdir', 'subsubfile1.txt'),
           p.join(root, 'packages', 'subsubdir', 'subsubfile2.txt')
         ]));
       });
     });
   });
 }