Use Entity in native_data.

pkg/compiler/lib/src/compiler.dart

 // Copyright (c) 2012, 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 dart2js.compiler_base;
 
 import 'dart:async' show EventSink, Future;
 
 import '../compiler_new.dart' as api;
 import 'closure.dart' as closureMapping show ClosureTask;
@@ skipping 1984 matching lines @@
   void forEachClassMember(
       ClassElement cls, void f(ClassElement declarer, MemberElement member)) {
     cls.ensureResolved(_resolution);
     cls.forEachMember((ClassElement declarer, MemberElement member) {
       if (member.isSynthesized) return;
       f(declarer, member);
     }, includeSuperAndInjectedMembers: true);
   }
 
   @override
+  ClassEntity getSuperClass(ClassElement cls) {
+    cls = cls.superclass;
+    while (cls != null && cls.isUnnamedMixinApplication) {
+      cls = cls.superclass;
+    }
+    return cls;
+  }
+
+  @override
   void forEachMixin(ClassElement cls, void f(ClassElement mixin)) {
     for (; cls != null; cls = cls.superclass) {
       if (cls.isMixinApplication) {
         MixinApplicationElement mixinApplication = cls;
         f(mixinApplication.mixin);
       }
     }
   }
 
   @override
@@ skipping 42 matching lines @@
     if (library != null && library.isSynthesized) {
       return null;
     }
     if (library == null && required) {
       throw new SpannableAssertionFailure(
           library, "The library '${uri}' was not found.");
     }
     return library;
   }
 }