Update navigation computer to include Element instead of id.

pkg/analysis_server/lib/src/constants.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.
 
 library constants;
 
 //
 // Server methods
 //
 const String SERVER_GET_VERSION = 'server.getVersion';
@@ skipping 89 matching lines @@
 const String OLD_LENGTH = 'oldLength';
 const String OPTIONS = 'options';
 const String OUTLINE = 'outline';
 const String PARAMETERS = 'parameters';
 const String PATTERN = 'pattern';
 const String REFACTORINGS = 'refactorings';
 const String REGIONS = 'regions';
 const String REMOVED = 'removed';
 const String RETURN_TYPE = 'returnType';
 const String SUBSCRIPTIONS = 'subscriptions';
+const String TARGETS = 'targets';
 const String TYPE = 'type';
 const String VERSION = 'version';
 
 //
 // Analysis option names
 //
 const String ANALYZE_ANGULAR = 'analyzeAngular'; // boolean
 const String ANALYZE_POLYMER = 'analyzePolymer'; // boolean
 const String ENABLE_ASYNC = 'enableAsync'; // boolean
 const String ENABLE_DEFERRED_LOADING = 'enableDeferredLoading'; // boolean
 const String ENABLE_ENUMS = 'enableEnums'; // boolean
 const String GENERATE_DART2JS_HINTS = 'generateDart2jsHints'; // boolean
 const String GENERATE_HINTS = 'generateHints'; // boolean