Fix bug when packages file changes in new driver

pkg/analysis_server/test/single_context_manager_test.dart

 // Copyright (c) 2016, 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 test.analysis_server.src.single_context_manager;
 
 import 'dart:core';
 
 import 'package:analysis_server/src/single_context_manager.dart';
 import 'package:analysis_server/src/utilities/null_string_sink.dart';
@@ skipping 46 matching lines @@
   String newFolder(List<String> pathComponents) {
     String folderPath = path.posix.joinAll(pathComponents);
     resourceProvider.newFolder(folderPath);
     return folderPath;
   }
 
   void setUp() {
     packageResolver = new TestUriResolver();
 
     _processRequiredPlugins();
-    DartSdkManager sdkManager = new DartSdkManager('', false);
+    DartSdkManager sdkManager = new DartSdkManager('/', false);
     manager = new SingleContextManager(resourceProvider, sdkManager,
         (_) => packageResolver, analysisFilesGlobs, new AnalysisOptionsImpl());
     PerformanceLog logger = new PerformanceLog(new NullStringSink());
     AnalysisDriverScheduler scheduler = new AnalysisDriverScheduler(logger);
-    callbacks =
-        new TestContextManagerCallbacks(resourceProvider, logger, scheduler);
+    callbacks = new TestContextManagerCallbacks(
+        resourceProvider, sdkManager, logger, scheduler);
     manager.callbacks = callbacks;
   }
 
   void test_isIgnored_false() {
     String project = '/project';
     resourceProvider.newFolder(project);
     manager.setRoots(<String>[project], <String>[], <String, String>{});
     expect(manager.isIgnored('$project/file.dart'), isFalse);
   }
 
@@ skipping 456 matching lines @@
     manager.processPlugins(plugins);
   }
 }
 
 class TestUriResolver extends UriResolver {
   @override
   Source resolveAbsolute(Uri uri, [Uri actualUri]) {
     return null;
   }
 }