Stop using Element.computeNode() in refactorings and fixes.

pkg/analysis_server/test/services/refactoring/abstract_refactoring.dart

Index: pkg/analysis_server/test/services/refactoring/abstract_refactoring.dart
diff --git a/pkg/analysis_server/test/services/refactoring/abstract_refactoring.dart b/pkg/analysis_server/test/services/refactoring/abstract_refactoring.dart
index a57c9888f782be85519ecab86303eec13e5ef357..68efbcc726604dae2326a6163b61ffcfb4abd2ad 100644
--- a/pkg/analysis_server/test/services/refactoring/abstract_refactoring.dart
+++ b/pkg/analysis_server/test/services/refactoring/abstract_refactoring.dart
@@ -22,6 +22,9 @@ import 'package:analysis_server/src/services/search/search_engine_internal2.dart
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart' show Element;
 import 'package:analyzer/file_system/file_system.dart';
+import 'package:analyzer/src/dart/analysis/ast_provider_context.dart';
+import 'package:analyzer/src/dart/analysis/ast_provider_driver.dart';
+import 'package:analyzer/src/dart/element/ast_provider.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:test/test.dart';
 
@@ -47,6 +50,7 @@ int findIdentifierLength(String search) {
 abstract class RefactoringTest extends AbstractSingleUnitTest {
   Index index;
   SearchEngine searchEngine;
+  AstProvider astProvider;
 
   SourceChange refactoringChange;
 
@@ -180,9 +184,11 @@ abstract class RefactoringTest extends AbstractSingleUnitTest {
     super.setUp();
     if (enableNewAnalysisDriver) {
       searchEngine = new SearchEngineImpl2([driver]);
+      astProvider = new AstProviderForDriver(driver);
     } else {
       index = createMemoryIndex();
       searchEngine = new SearchEngineImpl(index);
+      astProvider = new AstProviderForContext(context);
     }
   }
 }