Revert "Revert "Build new IR for functions returning a constant.""

sdk/lib/_internal/compiler/implementation/elements/modelx.dart

 // Copyright (c) 2013, 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 elements.modelx;
 
 import 'elements.dart';
 import '../../compiler.dart' as api;
 import '../tree/tree.dart';
 import '../util/util.dart';
@@ skipping 11 matching lines @@
                                  FunctionType,
                                  Selector,
                                  Constant,
                                  Compiler,
                                  isPrivateName;
 
 import '../dart_types.dart';
 
 import '../scanner/scannerlib.dart' show Token, EOF_TOKEN;
 
-
 class ElementX implements Element {
   static int elementHashCode = 0;
 
   final String name;
   final ElementKind kind;
   final Element enclosingElement;
   final int hashCode = ++elementHashCode;
   Link<MetadataAnnotation> metadata = const Link<MetadataAnnotation>();
 
   ElementX(this.name, this.kind, this.enclosingElement) {
@@ skipping 2338 matching lines @@
 
   MetadataAnnotation ensureResolved(Compiler compiler) {
     if (resolutionState == STATE_NOT_STARTED) {
       compiler.resolver.resolveMetadataAnnotation(this);
     }
     return this;
   }
 
   String toString() => 'MetadataAnnotation($value, $resolutionState)';
 }