Store constant variable initializers in elements.

pkg/compiler/lib/src/typechecker.dart

Index: pkg/compiler/lib/src/typechecker.dart
diff --git a/pkg/compiler/lib/src/typechecker.dart b/pkg/compiler/lib/src/typechecker.dart
index e186ee468711f781d11c2514f45f5d59ef6a8c7f..ea010299a6274570895bb558c12b60dc2642de3f 100644
--- a/pkg/compiler/lib/src/typechecker.dart
+++ b/pkg/compiler/lib/src/typechecker.dart
@@ -1953,8 +1953,10 @@ class TypeCheckerVisitor extends Visitor<DartType> {
         List<FieldElement> unreferencedFields = <FieldElement>[];
         EnumClassElement enumClass = expressionType.element;
         enumClass.enumValues.forEach((EnumConstantElement field) {
-          ConstantValue constantValue =
-              compiler.constants.getConstantValueForVariable(field);
+          // TODO(johnniwinther): Ensure that the enum constant is computed at
+          // this point.
+          ConstantValue constantValue = compiler.resolver.constantCompiler
+              .getConstantValueForVariable(field);
           if (constantValue == null) {
             // The field might not have been resolved.
             unreferencedFields.add(field);