Parse and resolve new syntax for named parameters.

dart/lib/compiler/implementation/resolver.dart

Index: dart/lib/compiler/implementation/resolver.dart
diff --git a/dart/lib/compiler/implementation/resolver.dart b/dart/lib/compiler/implementation/resolver.dart
index 9bec4367defffc025f59fb2bb033cacec06e826a..afc79e0c9fbb8b0e60db0bb113034f552bb4c75c 100644
--- a/dart/lib/compiler/implementation/resolver.dart
+++ b/dart/lib/compiler/implementation/resolver.dart
@@ -2325,7 +2325,8 @@ class SignatureResolver extends CommonResolverVisitor<Element> {
 
   Element visitNodeList(NodeList node) {
     // This must be a list of optional arguments.
-    if (node.beginToken.stringValue !== '[') {
+    String value = node.beginToken.stringValue;
+    if ((value !== '[') && (value !== '{')) {
       internalError(node, "expected optional parameters");
     }
     LinkBuilder<Element> elements = analyzeNodes(node.nodes);