Fix context creation in tests

pkg/analyzer/test/src/mock_sdk.dart

Index: pkg/analyzer/test/src/mock_sdk.dart
diff --git a/pkg/analyzer/test/src/mock_sdk.dart b/pkg/analyzer/test/src/mock_sdk.dart
index 7cadfcc5b7db566df235908c22cd80f1a5a8a634..1487f4ab0f915fb38a21fa95b6cedd2a08e09276 100644
--- a/pkg/analyzer/test/src/mock_sdk.dart
+++ b/pkg/analyzer/test/src/mock_sdk.dart
@@ -6,6 +6,7 @@ library test.src.mock_sdk;
 
 import 'package:analyzer/file_system/file_system.dart' as resource;
 import 'package:analyzer/file_system/memory_file_system.dart' as resource;
+import 'package:analyzer/src/context/context.dart' as newContext;
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/source.dart';
@@ -188,7 +189,11 @@ class HtmlElement {}
   @override
   AnalysisContext get context {
     if (_analysisContext == null) {
-      _analysisContext = new SdkAnalysisContext();
+      if (AnalysisEngine.instance.useTaskModel) {
+        _analysisContext = new newContext.SdkAnalysisContext();
+      } else {
+        _analysisContext = new SdkAnalysisContext();
+      }
       SourceFactory factory = new SourceFactory([new DartUriResolver(this)]);
       _analysisContext.sourceFactory = factory;
       ChangeSet changeSet = new ChangeSet();