Add model test of CodegenWorldBuilder to compile_from_dill_test

pkg/compiler/lib/src/universe/member_usage.dart

 // Copyright (c) 2017, 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.
 
 part of world_builder;
 
 abstract class _AbstractUsage<T> {
   final EnumSet<T> _pendingUse = new EnumSet<T>();
 
   _AbstractUsage() {
     _pendingUse.addAll(_originalUse);
   }
 
   /// Returns the possible uses of [entity] that have not yet been registered.
   EnumSet<T> get pendingUse => _pendingUse;
 
   /// Returns the uses of [entity] that have been registered.
   EnumSet<T> get appliedUse => _originalUse.minus(_pendingUse);
 
   EnumSet<T> get _originalUse;
 
   /// `true` if the [appliedUse] is non-empty.
   bool get hasUse => appliedUse.isNotEmpty;
+
+  int get hashCode => _originalUse.hashCode * 13 + _pendingUse.hashCode * 17;
+
+  bool operator ==(other) {
+    if (identical(this, other)) return true;
+    if (other is! _AbstractUsage) return false;
+    return _originalUse.value == other._originalUse.value &&
+        _pendingUse.value == other._pendingUse.value;
+  }
 }
 
 /// Registry for the observed use of a member [entity] in the open world.
 abstract class _MemberUsage extends _AbstractUsage<MemberUse> {
   // TODO(johnniwinther): Change [Entity] to [MemberEntity].
   final Entity entity;
 
   _MemberUsage.internal(this.entity);
 
   factory _MemberUsage(MemberEntity member, {bool isNative: false}) {
@@ skipping 338 matching lines @@
     if (hasClosurization) {
       return MemberUses.NONE;
     }
     hasNormalUse = hasClosurization = true;
     return _pendingUse.removeAll(MemberUses.ALL_STATIC);
   }
 
   @override
   EnumSet<MemberUse> get _originalUse => MemberUses.ALL_STATIC;
 }