Fixes for AST <-> binary serialization.

pkg/kernel/lib/binary/ast_to_binary.dart

 // Copyright (c) 2016, 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 kernel.ast_to_binary;
 
 import '../ast.dart';
 import '../import_table.dart';
 import 'tag.dart';
 import 'dart:convert';
 import 'dart:typed_data';
@@ skipping 362 matching lines @@
     writeNode(annotation);
   }
 
   void writeAnnotationList(List<Expression> annotations) {
     writeList(annotations, writeAnnotation);
   }
 
   int _encodeClassFlags(bool isAbstract, bool isEnum,
       bool isSyntheticMixinImplementation, ClassLevel level) {
     int abstractFlag = isAbstract ? 1 : 0;
-    int isEnumFlag = isSyntheticMixinImplementation ? 2 : 0;
+    int isEnumFlag = isEnum ? 2 : 0;
     int isSyntheticMixinImplementationFlag =
         isSyntheticMixinImplementation ? 4 : 0;
     int levelFlags = (level.index - 1) << 3;
     return abstractFlag |
         isEnumFlag |
         isSyntheticMixinImplementationFlag |
         levelFlags;
   }
 
   visitClass(Class node) {
@@ skipping 1159 matching lines @@
     _sink.add(_buffer.sublist(0, length));
     _buffer = new Uint8List(SIZE);
     flushedLength += length;
     length = 0;
   }
 
   void flushAndDestroy() {
     _sink.add(_buffer.sublist(0, length));
   }
 }