Add ConstantUse to WorldImpact

pkg/compiler/lib/src/serialization/impact_serialization.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 dart2js.serialization.impact;
 
 import '../common/resolution.dart';
 import '../constants/expressions.dart';
 import '../elements/resolution_types.dart';
 import '../elements/elements.dart';
@@ skipping 73 matching lines @@
       object.setType(Key.TYPE, staticUse.type);
     }
   }
 
   @override
   void visitTypeUse(TypeUse typeUse) {
     ObjectEncoder object = typeUses.createObject();
     object.setEnum(Key.KIND, typeUse.kind);
     object.setType(Key.TYPE, typeUse.type);
   }
+
+  @override
+  void visitConstantUse(ConstantUse typeUse) {
+    throw new UnsupportedError("ConstantUse serialization is not supported.");
+  }
 }
 
 /// A deserialized [WorldImpact] object.
 class DeserializedResolutionImpact extends WorldImpact
     implements ResolutionImpact {
   final Iterable<String> constSymbolNames;
   final Iterable<ConstantExpression> constantLiterals;
   final Iterable<DynamicUse> dynamicUses;
   final EnumSet<Feature> _features;
   final Iterable<ListLiteralUse> listLiterals;
@@ skipping 114 matching lines @@
         constantLiterals: constantLiterals,
         dynamicUses: dynamicUses,
         features: features,
         listLiterals: listLiterals,
         mapLiterals: mapLiterals,
         staticUses: staticUses,
         typeUses: typeUses,
         nativeData: nativeData);
   }
 }