Support for modular mixin resolution.

pkg/kernel/lib/binary/ast_from_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_from_binary;
 
 import '../ast.dart';
 import 'tag.dart';
 import 'loader.dart';
 import 'dart:convert';
 import 'package:kernel/transformations/flags.dart';
@@ skipping 306 matching lines @@
         break;
       default:
         throw fail('Invalid class tag: $tag');
     }
   }
 
   void readNormalClass(Class node) {
     node.fileOffset = readOffset();
     int flags = readByte();
     node.isAbstract = flags & 0x1 != 0;
-    node.level = _currentLibrary.isExternal
-        ? (flags & 0x2 != 0) ? ClassLevel.Type : ClassLevel.Hierarchy
-        : ClassLevel.Body;
+    int levelIndex = (flags >> 1) & 0x3;
+    node.level = ClassLevel.values[levelIndex + 1];
     node.name = readStringOrNullIfEmpty();
     node.fileUri = readUriReference();
     node.annotations = readAnnotationList(node);
     debugPath.add(node.name ?? 'normal-class');
     readAndPushTypeParameterList(node.typeParameters, node);
     node.supertype = readSupertypeOption();
     _fillNonTreeNodeList(node.implementedTypes, readSupertype);
     _fillLazilyLoadedList(node.fields, (int tag, int index) {
       readField(loader.getClassMemberReference(node, tag, index), tag);
     });
     _fillLazilyLoadedList(node.constructors, (int tag, int index) {
       readConstructor(loader.getClassMemberReference(node, tag, index), tag);
     });
     _fillLazilyLoadedList(node.procedures, (int tag, int index) {
       readProcedure(loader.getClassMemberReference(node, tag, index), tag);
     });
     typeParameterStack.length = 0;
     debugPath.removeLast();
   }
 
   void readMixinClass(Class node) {
     node.fileOffset = readOffset();
     int flags = readByte();
     node.isAbstract = flags & 0x1 != 0;
-    node.level = _currentLibrary.isExternal
-        ? (flags & 0x2 != 0) ? ClassLevel.Type : ClassLevel.Hierarchy
-        : ClassLevel.Body;
+    int levelIndex = (flags >> 1) & 0x3;
+    node.level = ClassLevel.values[levelIndex];
     node.name = readStringOrNullIfEmpty();
     node.fileUri = readUriReference();
     node.annotations = readAnnotationList(node);
     debugPath.add(node.name ?? 'mixin-class');
     readAndPushTypeParameterList(node.typeParameters, node);
     node.supertype = readSupertype();
     node.mixedInType = readSupertype();
     _fillNonTreeNodeList(node.implementedTypes, readDartType);
     _fillLazilyLoadedList(node.constructors, (int tag, int index) {
       readConstructor(loader.getClassMemberReference(node, tag, index), tag);
@@ skipping 601 matching lines @@
         isFinal: flags & 0x1 != 0,
         isConst: flags & 0x2 != 0)..fileOffset = offset;
   }
 
   int readOffset() {
     // Offset is saved as unsigned,
     // but actually ranges from -1 and up (thus the -1)
     return readUInt() - 1;
   }
 }