Generalize DartSdkManager to support embedder SDKs

pkg/analysis_server/test/domain_diagnostic_test.dart

Index: pkg/analysis_server/test/domain_diagnostic_test.dart
diff --git a/pkg/analysis_server/test/domain_diagnostic_test.dart b/pkg/analysis_server/test/domain_diagnostic_test.dart
index d2288ae32f2af535c230096a0cff71d0c23b0916..3a6f3cb3ceac8ae070249457f994967fc99107f8 100644
--- a/pkg/analysis_server/test/domain_diagnostic_test.dart
+++ b/pkg/analysis_server/test/domain_diagnostic_test.dart
@@ -11,6 +11,7 @@ import 'package:analysis_server/src/plugin/server_plugin.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/instrumentation/instrumentation.dart';
 import 'package:analyzer/src/generated/engine.dart';
+import 'package:analyzer/src/generated/sdk.dart';
 import 'package:plugin/manager.dart';
 import 'package:plugin/plugin.dart';
 import 'package:unittest/unittest.dart';
@@ -53,7 +54,7 @@ main() {
         null,
         serverPlugin,
         new AnalysisServerOptions(),
-        (_) => new MockSdk(),
+        new DartSdkManager('', false, (_) => new MockSdk()),
         InstrumentationService.NULL_SERVICE);
     handler = new DiagnosticDomainHandler(server);
   });