Flush entries for unreferenced sources

pkg/analyzer/test/generated/engine_test.dart

 // Copyright (c) 2014, 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.
 
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.engine_test;
 
 import 'dart:async';
@@ skipping 2686 matching lines @@
     expect(entry.hasInvalidData(DartEntry.RESOLUTION_ERRORS), isTrue);
     expect(entry.hasInvalidData(DartEntry.RESOLVED_UNIT), isTrue);
     expect(entry.hasInvalidData(DartEntry.VERIFICATION_ERRORS), isTrue);
   }
 
   void test_invalidateAllInformation() {
     Source librarySource = new TestSource();
     DartEntry entry = _entryWithValidState(librarySource);
     entry.invalidateAllInformation();
     expect(entry.getState(SourceEntry.CONTENT), same(CacheState.INVALID));
-    expect(entry.getState(SourceEntry.CONTENT_ERRORS), same(CacheState.INVALID));
+    expect(
+        entry.getState(SourceEntry.CONTENT_ERRORS),
+        same(CacheState.INVALID));
     expect(entry.getState(SourceEntry.LINE_INFO), same(CacheState.INVALID));
     expect(
         entry.getState(DartEntry.CONTAINING_LIBRARIES),
         same(CacheState.VALID));
     expect(entry.getState(DartEntry.ELEMENT), same(CacheState.INVALID));
     expect(
         entry.getState(DartEntry.EXPORTED_LIBRARIES),
         same(CacheState.INVALID));
     expect(
         entry.getState(DartEntry.IMPORTED_LIBRARIES),
@@ skipping 4428 matching lines @@
 
 
 class _Source_getContent_throwException extends NonExistingSource {
   _Source_getContent_throwException(String name)
       : super(name, UriKind.FILE_URI);
 
   @override
   TimestampedData<String> get contents {
     throw 'Read error';
   }
+
+  @override
+  bool exists() => true;
 }
 
 
 class _UniversalCachePartitionTest_test_setMaxCacheSize implements
     CacheRetentionPolicy {
   @override
   RetentionPriority getAstPriority(Source source, SourceEntry sourceEntry) =>
       RetentionPriority.LOW;
 }