Fix incremental element builder for added enums.

pkg/analyzer/lib/src/task/incremental_element_builder.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.incremental_element_builder;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
@@ skipping 115 matching lines @@
    * same order as in [newUnit]. Existing resolution is kept where possible.
    *
    * Updates [unitElement] by adding/removing elements as needed.
    *
    * Fills [unitDelta] with added/remove elements.
    */
   void build() {
     _materializeLazyElements();
     new CompilationUnitBuilder()
         .buildCompilationUnit(unitSource, newUnit, librarySource);
+    newUnit.accept(new EnumMemberBuilder(unitElement.context.typeProvider));
     _processDirectives();
     _processUnitMembers();
     _replaceUnitContents(oldUnit, newUnit);
     _findConstants();
     newUnit.element = unitElement;
     unitElement.setCodeRange(0, newUnit.endToken.end);
   }
 
   void _addElementToUnitHolder(Element element) {
     if (element is ClassElement) {
@@ skipping 589 matching lines @@
             } else if (element is ParameterElementImpl) {
               element.setVisibleRange(newOffset, newLength);
             }
           }
         }
       }
     }
     super.visitElement(element);
   }
 }