Add self-reference sources into INCLUDED_PARTS.

pkg/analyzer/lib/src/task/dart.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;
 
 import 'dart:collection';
 import 'dart:math' as math;
 
 import 'package:analyzer/src/context/cache.dart';
@@ skipping 2708 matching lines @@
         hasNonPartOfDirective = true;
         if (directive is UriBasedDirective) {
           Source referencedSource =
               resolveDirective(context, source, directive, errorListener);
           if (referencedSource != null) {
             if (directive is ExportDirective) {
               exportedSourceSet.add(referencedSource);
             } else if (directive is ImportDirective) {
               explicitlyImportedSourceSet.add(referencedSource);
             } else if (directive is PartDirective) {
-              if (referencedSource != source) {
-                includedSourceSet.add(referencedSource);
-              }
+              includedSourceSet.add(referencedSource);
             } else {
               throw new AnalysisException(
                   '$runtimeType failed to handle a ${directive.runtimeType}');
             }
           }
         }
       }
     }
     //
     // Always include "dart:core" source.
@@ skipping 784 matching lines @@
   @override
   bool moveNext() {
     if (_newSources.isEmpty) {
       return false;
     }
     currentTarget = _newSources.first;
     _newSources.remove(currentTarget);
     return true;
   }
 }