Add UnlinkedClass.hasNoSupertype property to summaries.

pkg/analyzer/lib/src/summary/resynthesize.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 summary_resynthesizer;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/element_handle.dart';
 import 'package:analyzer/src/generated/engine.dart';
@@ skipping 232 matching lines @@
       for (int i = 0; i < serializedClass.typeParameters.length; i++) {
         finishTypeParameter(
             serializedClass.typeParameters[i], currentTypeParameters[i]);
       }
       ClassElementImpl classElement =
           new ClassElementImpl(serializedClass.name, -1);
       classElement.mixinApplication = serializedClass.isMixinApplication;
       InterfaceTypeImpl correspondingType = new InterfaceTypeImpl(classElement);
       if (serializedClass.supertype != null) {
         classElement.supertype = buildType(serializedClass.supertype);
-      } else {
-        // TODO(paulberry): don't make Object point to itself.
+      } else if (!serializedClass.hasNoSupertype) {
         classElement.supertype = summaryResynthesizer.typeProvider.objectType;
       }
       classElement.interfaces =
           serializedClass.interfaces.map(buildType).toList();
       classElement.mixins = serializedClass.mixins.map(buildType).toList();
       classElement.typeParameters = currentTypeParameters;
       ElementHolder memberHolder = new ElementHolder();
       bool constructorFound = false;
       for (UnlinkedExecutable serializedExecutable
           in serializedClass.executables) {
@@ skipping 653 matching lines @@
       elementMap[cls.name] = cls;
     }
     for (FunctionTypeAliasElement typeAlias in unit.functionTypeAliases) {
       elementMap[typeAlias.name] = typeAlias;
     }
     resummarizedElements[absoluteUri] = elementMap;
     unitHolder = null;
     prelinkedUnit = null;
   }
 }