Add runtimeType() to Object which returns canonicalized instances of Type.

lib/compiler/implementation/lib/js_helper.dart

Index: lib/compiler/implementation/lib/js_helper.dart
diff --git a/lib/compiler/implementation/lib/js_helper.dart b/lib/compiler/implementation/lib/js_helper.dart
index e03c863bab5200f3b6476b4458b39775c83c6337..429f12dee4ec4f1cb7f9f2f0edf988d4073b68cf 100644
--- a/lib/compiler/implementation/lib/js_helper.dart
+++ b/lib/compiler/implementation/lib/js_helper.dart
@@ -1324,3 +1324,23 @@ void throwNoSuchMethod(obj, name, arguments) {
 void throwCyclicInit(String staticName) {
   throw new RuntimeError("Cyclic initialization for static $staticName");
 }
+
+class TypeImpl implements Type {
+  final String typeName;
+  TypeImpl(this.typeName);
+  toString() => typeName;
+}
+
+Type getOrCreateCachedRuntimeType(String key) {
+  Type runtimeType = JS('Object', @'$.runtimeTypeCache[#]', key);

[ngeoffray, 2012/09/17 15:31:14]

'Object' -> 'Type'

[ngeoffray, 2012/09/17 15:31:14]

Please use JS_CURRENT_ISOLATE() instead of $.

[karlklose, 2012/09/19 06:40:45]

Done.

[karlklose, 2012/09/19 06:40:45]

Done.

+  if (runtimeType == null) {
+    runtimeType = new TypeImpl(key);
+    JS('void', @'$.runtimeTypeCache[#] = #', key, runtimeType);

[ngeoffray, 2012/09/17 15:31:14]

ditto

[karlklose, 2012/09/19 06:40:45]

Done.

+  }
+  return runtimeType;
+}
+
+String getRuntimeTypeString(var object) {
+  var typeInfo = JS('Object', @'#.builtin$typeInfo', object);
+  return JS('String', @'#.runtimeType', typeInfo);
+}