Add an analysis option to disable cache flushing.

pkg/analyzer/test/src/task/dart_work_manager_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 analyzer.test.src.task.dart_work_manager_test;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/error/error.dart' show AnalysisError;
 import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/dart/scanner/scanner.dart' show ScannerErrorCode;
 import 'package:analyzer/src/generated/engine.dart'
     show
         AnalysisErrorInfoImpl,
+        AnalysisOptions,
+        AnalysisOptionsImpl,
         CacheState,
         ChangeNoticeImpl,
         InternalAnalysisContext;
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/testing/ast_factory.dart';
 import 'package:analyzer/src/task/dart.dart';
 import 'package:analyzer/src/task/dart_work_manager.dart';
 import 'package:analyzer/task/dart.dart';
 import 'package:analyzer/task/general.dart';
@@ skipping 795 matching lines @@
     implements InternalAnalysisContext {
   @override
   CachePartition privateAnalysisCachePartition;
 
   @override
   AnalysisCache analysisCache;
 
   Map<Source, ChangeNoticeImpl> _pendingNotices = <Source, ChangeNoticeImpl>{};
 
   @override
+  final AnalysisOptions analysisOptions = new AnalysisOptionsImpl();
+
+  @override
   final ReentrantSynchronousStream<InvalidatedResult> onResultInvalidated =
       new ReentrantSynchronousStream<InvalidatedResult>();
 
   _InternalAnalysisContextMock() {
     privateAnalysisCachePartition = new UniversalCachePartition(this);
     analysisCache = new AnalysisCache([privateAnalysisCachePartition]);
     analysisCache.onResultInvalidated.listen((InvalidatedResult event) {
       onResultInvalidated.add(event);
     });
   }
@@ skipping 18 matching lines @@
 class _SourceFactoryMock extends TypedMock implements SourceFactory {}
 
 class _SourceMock extends TypedMock implements Source {
   final String shortName;
   _SourceMock(this.shortName);
   @override
   String get fullName => '/' + shortName;
   @override
   String toString() => fullName;
 }