Enable async support

pkg/analyzer/lib/src/analyzer_impl.dart

 // Copyright (c) 2013, 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_impl;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:io';
 
@@ skipping 160 matching lines @@
         declaredVariables.define(variableName, value);
       });
     }
     // Uncomment the following to have errors reported on stdout and stderr
     AnalysisEngine.instance.logger = new StdLogger(options.log);
 
     // set options for context
     AnalysisOptionsImpl contextOptions = new AnalysisOptionsImpl();
     contextOptions.cacheSize = _MAX_CACHE_SIZE;
     contextOptions.hint = !options.disableHints;
-    contextOptions.enableAsync = options.enableAsync;
     contextOptions.enableEnum = options.enableEnum;
     context.analysisOptions = contextOptions;
 
     // Create and add a ChangeSet
     ChangeSet changeSet = new ChangeSet();
     changeSet.addedSource(source);
     context.applyChanges(changeSet);
   }
 
   /// Fills [errorInfos] using [sources].
@@ skipping 255 matching lines @@
     }
   }
 
   @override
   void logInformation2(String message, Object exception) {
     if (log) {
       stdout.writeln(message);
     }
   }
 }