Support static/global field initializations.

frog/leg/resolver.dart

 // Copyright (c) 2011, 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.
 
 class TreeElements {
   Map<Node, Element> map;
   TreeElements() : map = new LinkedHashMap<Node, Element>();
   operator []=(Node node, Element element) => map[node] = element;
   operator [](Node node) => map[node];
 }
@@ skipping 39 matching lines @@
     while (!toResolve.isEmpty()) {
       toResolve.removeFirst().resolve(compiler);
     }
     return visitor.mapping;
   }
 
   TreeElements resolveFieldElement(Element element) {
     Node tree = element.parseNode(compiler, compiler);
     ResolverVisitor visitor = new FullResolverVisitor(compiler, element);
     if (tree is SendSet) {
-      compiler.unimplemented("Field initializers", node: tree);
       SendSet send = tree;
       visitor.visit(send.arguments.head);
     }
     return visitor.mapping;
   }
 
   bool isInitializer(SendSet node) {
     if (node.selector.asIdentifier() == null) return false;
     if (node.receiver == null) return true;
     if (node.receiver.asIdentifier() == null) return false;
@@ skipping 709 matching lines @@
 class TopScope extends Scope {
   Universe universe;
 
   TopScope(Universe this.universe) : super(null, null);
   Element lookup(SourceString name) => universe.find(name);
 
   Element add(Element element) {
     throw "Cannot add an element in the top scope";
   }
 }