Make use of test_flushAstStructures in analysis server.

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/src/constants.dart';
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analyzer/file_system/file_system.dart';
@@ skipping 187 matching lines @@
   test_sendNoticesAfterNopChange_flushedUnit() async {
     createProject();
     addTestFile('');
     await server.onAnalysisComplete;
     // add an overlay
     server.updateContent(
         '1', {testFile: new AddContentOverlay('main() {} main() {}')});
     await server.onAnalysisComplete;
     // clear errors and make a no-op change
     filesErrors.clear();
-    server.test_flushResolvedUnit(testFile);
+    server.test_flushAstStructures(testFile);
     server.updateContent('2', {
       testFile: new ChangeContentOverlay([new SourceEdit(0, 4, 'main')])
     });
     await server.onAnalysisComplete;
     // errors should have been resent
     expect(filesErrors, isNotEmpty);
   }
 
   List<Source> _getUserSources(AnalysisContext context) {
     List<Source> sources = <Source>[];
@@ skipping 13 matching lines @@
 
   @override
   bool matches(arg) {
     return arg is CompilationUnit && arg.element.source.fullName == file;
   }
 }
 
 class _MockIndex extends TypedMock implements Index {
   noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 }