Remove unused method and field from DartSdkManager

pkg/analysis_server/test/analysis_server_test.dart

Index: pkg/analysis_server/test/analysis_server_test.dart
diff --git a/pkg/analysis_server/test/analysis_server_test.dart b/pkg/analysis_server/test/analysis_server_test.dart
index 9c632f9f8aeb52b00eab8efe417023e541c56fc8..a76d57bc6a137614ea34b1eda7c8cefe26595b50 100644
--- a/pkg/analysis_server/test/analysis_server_test.dart
+++ b/pkg/analysis_server/test/analysis_server_test.dart
@@ -137,7 +137,8 @@ import "../foo/foo.dart";
     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,
@@ -146,7 +147,7 @@ import "../foo/foo.dart";
         null,
         plugin,
         new AnalysisServerOptions(),
-        new DartSdkManager('/', false, (_) => sdk),
+        new DartSdkManager('/', false),
         InstrumentationService.NULL_SERVICE,
         rethrowExceptions: true);
     processRequiredPlugins();