Remove unused method and field from DartSdkManager

pkg/analysis_server/test/domain_analysis_test.dart

Index: pkg/analysis_server/test/domain_analysis_test.dart
diff --git a/pkg/analysis_server/test/domain_analysis_test.dart b/pkg/analysis_server/test/domain_analysis_test.dart
index 1f760df0ca361540d889b91aac379e7365eecf0f..76d12c8586b7a8a34bba4f7de34ccb25b5e2b30d 100644
--- a/pkg/analysis_server/test/domain_analysis_test.dart
+++ b/pkg/analysis_server/test/domain_analysis_test.dart
@@ -23,7 +23,6 @@ import 'mock_sdk.dart';
 import 'mocks.dart';
 
 main() {
-
   defineReflectiveSuite(() {
     defineReflectiveTests(AnalysisDomainTest);
     defineReflectiveTests(SetSubscriptionsTest);
@@ -40,7 +39,8 @@ main() {
     ExtensionManager manager = new ExtensionManager();
     ServerPlugin serverPlugin = new ServerPlugin();
     manager.processPlugins([serverPlugin]);
-    MockSdk sdk = new MockSdk(resourceProvider: resourceProvider);
+    // Create an SDK in the mock file system.
+    new MockSdk(resourceProvider: resourceProvider);
     server = new AnalysisServer(
         serverChannel,
         resourceProvider,
@@ -48,7 +48,7 @@ main() {
         null,
         serverPlugin,
         new AnalysisServerOptions(),
-        new DartSdkManager('/', false, (_) => sdk),
+        new DartSdkManager('/', false),
         InstrumentationService.NULL_SERVICE);
     handler = new AnalysisDomainHandler(server);
   });
@@ -435,7 +435,8 @@ class AnalysisTestHelper {
     ExtensionManager manager = new ExtensionManager();
     ServerPlugin serverPlugin = new ServerPlugin();
     manager.processPlugins([serverPlugin]);
-    MockSdk sdk = new MockSdk(resourceProvider: resourceProvider);
+    // Create an SDK in the mock file system.
+    new MockSdk(resourceProvider: resourceProvider);
     server = new AnalysisServer(
         serverChannel,
         resourceProvider,
@@ -443,7 +444,7 @@ class AnalysisTestHelper {
         null,
         serverPlugin,
         new AnalysisServerOptions(),
-        new DartSdkManager('/', false, (_) => sdk),
+        new DartSdkManager('/', false),
         InstrumentationService.NULL_SERVICE);
     handler = new AnalysisDomainHandler(server);
     // listen for notifications