Don't schedule LIBRARY_ERRORS_READY for libraries that should not be analyzed.

pkg/analyzer/lib/src/task/dart_work_manager.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.src.task.dart_work_manager;
 
 import 'dart:collection';
 
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/generated/engine.dart'
     show
         AnalysisEngine,
         AnalysisErrorInfo,
         AnalysisErrorInfoImpl,
+        AnalysisOptions,
         CacheState,
         InternalAnalysisContext;
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/utilities_collection.dart';
 import 'package:analyzer/src/task/dart.dart';
 import 'package:analyzer/src/task/driver.dart';
 import 'package:analyzer/task/dart.dart';
 import 'package:analyzer/task/general.dart';
 import 'package:analyzer/task/model.dart';
@@ skipping 222 matching lines @@
   }
 
   @override
   void resultsComputed(
       AnalysisTarget target, Map<ResultDescriptor, dynamic> outputs) {
     // Organize sources.
     if (_isDartSource(target)) {
       SourceKind kind = outputs[SOURCE_KIND];
       if (kind != null) {
         unknownSourceQueue.remove(target);
-        if (kind == SourceKind.LIBRARY) {
+        if (kind == SourceKind.LIBRARY &&
+            context.shouldErrorsBeAnalyzed(target, null)) {
           librarySourceQueue.add(target);
         }
       }
     }
     // Update parts in libraries.
     if (_isDartSource(target)) {
       Source library = target;
       List<Source> includedParts = outputs[INCLUDED_PARTS];
       if (includedParts != null) {
         libraryPartsMap[library] = includedParts;
@@ skipping 69 matching lines @@
 
   static bool _isDartSource(AnalysisTarget target) {
     return target is Source && AnalysisEngine.isDartFileName(target.fullName);
   }
 
   static bool _isErrorResult(ResultDescriptor descriptor) {
     return _SOURCE_ERRORS.contains(descriptor) ||
         _UNIT_ERRORS.contains(descriptor);
   }
 }