Use ConstExp for storing constants.

sdk/lib/_internal/compiler/implementation/mirrors/dart2js_mirrors.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.mirrors;
 
 import 'dart:collection' show UnmodifiableListView, UnmodifiableMapView;
 
+import '../cps_ir/const_expression.dart';
 import '../elements/elements.dart';
 import '../scanner/scannerlib.dart';
 import '../resolution/resolution.dart' show Scope;
 import '../dart2jslib.dart';
 import '../dart_types.dart';
 import '../tree/tree.dart';
 import '../util/util.dart'
     show Link,
          LinkBuilder;
 import '../util/characters.dart' show $CR, $LF;
@@ skipping 195 matching lines @@
     }
   }
 
   List<InstanceMirror> get metadata {
     if (_metadata == null) {
       _metadata = <InstanceMirror>[];
       for (MetadataAnnotation metadata in _element.metadata) {
         _appendCommentTokens(
             mirrorSystem.compiler.commentMap[metadata.beginToken]);
         metadata.ensureResolved(mirrorSystem.compiler);
-        _metadata.add(_convertConstantToInstanceMirror(mirrorSystem,
-                                                       metadata.value));
+        _metadata.add(_convertConstantToInstanceMirror(
+            mirrorSystem, metadata.constant, metadata.constant.value));
       }
       _appendCommentTokens(mirrorSystem.compiler.commentMap[getBeginToken()]);
     }
     // TODO(johnniwinther): Return an unmodifiable list instead.
     return new List<InstanceMirror>.from(_metadata);
   }
 
   DeclarationMirror lookupInScope(String name) {
     // TODO(11653): Support lookup of constructors.
     Scope scope = _element.buildScope();
@@ skipping 254 matching lines @@
   }
 
   static ResolvedNode defaultValueSyntaxOf(Dart2JsParameterMirror parameter) {
     if (!parameter.hasDefaultValue) return null;
     ParameterElement parameterElement = parameter._element;
     var node = parameterElement.initializer;
     var treeElements = parameterElement.treeElements;
     return new ResolvedNode(node, treeElements, parameter.mirrorSystem);
   }
 }