Remove unused method and field from DartSdkManager

pkg/analysis_server/test/analysis_server_test.dart

 // Copyright (c) 2014, 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;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/analysis_server.dart';
@@ skipping 119 matching lines @@
     ExtensionManager manager = new ExtensionManager();
     manager.processPlugins(plugins);
   }
 
   void setUp() {
     ExtensionManager manager = new ExtensionManager();
     ServerPlugin plugin = new ServerPlugin();
     manager.processPlugins([plugin]);
     channel = new MockServerChannel();
     resourceProvider = new MemoryResourceProvider();
-    MockSdk sdk = new MockSdk(resourceProvider: resourceProvider);
+    // Create an SDK in the mock file system.
+    new MockSdk(resourceProvider: resourceProvider);
     packageMapProvider = new MockPackageMapProvider();
     server = new AnalysisServer(
         channel,
         resourceProvider,
         packageMapProvider,
         null,
         plugin,
         new AnalysisServerOptions(),
-        new DartSdkManager('/', false, (_) => sdk),
+        new DartSdkManager('/', false),
         InstrumentationService.NULL_SERVICE,
         rethrowExceptions: true);
     processRequiredPlugins();
   }
 
   Future test_contextDisposed() {
     resourceProvider.newFolder('/foo');
     resourceProvider.newFile('/foo/bar.dart', 'library lib;');
     server.setAnalysisRoots('0', ['/foo'], [], {});
     AnalysisContext context;
@@ skipping 409 matching lines @@
   _MockServerOperation(this.context);
 
   @override
   ServerOperationPriority get priority => ServerOperationPriority.ANALYSIS;
 
   @override
   void perform(AnalysisServer server) {
     isComplete = true;
   }
 }