Prepare for decoupling analyzer ASTs from element model.

pkg/analysis_server/test/analysis/update_content_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library test.analysis.updateContent;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/resolution_accessors.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 import 'package:typed_mock/typed_mock.dart';
 
 import '../analysis_abstract.dart';
 
 main() {
@@ skipping 264 matching lines @@
   }
 }
 
 class _ArgumentMatcher_CompilationUnit extends ArgumentMatcher {
   final String file;
 
   _ArgumentMatcher_CompilationUnit(this.file);
 
   @override
   bool matches(arg) {
-    return arg is CompilationUnit && arg.element.source.fullName == file;
+    return arg is CompilationUnit &&
+        elementForCompilationUnit(arg).source.fullName == file;
   }
 }
 
 class _MockIndex extends TypedMock implements Index {}