Record names of constructors and use that to implement Object.toString.

dart/frog/leg/lib/core.dart

Index: dart/frog/leg/lib/core.dart
diff --git a/dart/frog/leg/lib/core.dart b/dart/frog/leg/lib/core.dart
index 30a517b6174dcbb244ba5c8b5817862c489e20a4..b81ca3e9a9cad11363da04e96427ca357002b3f5 100644
--- a/dart/frog/leg/lib/core.dart
+++ b/dart/frog/leg/lib/core.dart
@@ -303,7 +303,9 @@ class int {}
 class double {}
 class String {}
 class bool {}
-class Object {}
+class Object {
+  toString() => "[Instance of '${JS('String', @'this.constructor.name')}']";

[Lasse Reichstein, 2012/01/11 09:49:16]

and @'this.constructor.$name' here.

+}
 class List<T> {
   static void _checkConstructorInput(n) {
     // TODO(ngeoffray): Inline once we support optional parameters or