Store constant variable initializers in elements.

pkg/compiler/lib/src/resolution/resolution.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.resolution;
 
 import 'dart:collection' show Queue;
 
 import '../common.dart';
 import '../common/names.dart' show Identifiers;
@@ skipping 358 matching lines @@
     } else {
       // TODO(johnniwinther): Register a feature instead.
       registry.registerTypeUse(new TypeUse.instantiation(coreTypes.nullType));
     }
 
     if (Elements.isStaticOrTopLevelField(element)) {
       visitor.addDeferredAction(element, () {
         if (element.modifiers.isConst) {
           element.constant = constantCompiler.compileConstant(element);
         } else {
-          constantCompiler.compileVariable(element);
+          element.constant = constantCompiler.compileVariable(element);
         }
       });
       if (initializer != null) {
         if (!element.modifiers.isConst) {
           // TODO(johnniwinther): Determine the const-ness eagerly to avoid
           // unnecessary registrations.
           registry.registerFeature(Feature.LAZY_FIELD);
         }
       }
     }
@@ skipping 700 matching lines @@
   TreeElements get treeElements {
     assert(invariant(this, _treeElements != null,
         message: "TreeElements have not been computed for $this."));
     return _treeElements;
   }
 
   void reuseElement() {
     _treeElements = null;
   }
 }