Changes to allow more precise inference of live native classes.

sdk/lib/_internal/compiler/implementation/lib/isolate_patch.dart

Index: sdk/lib/_internal/compiler/implementation/lib/isolate_patch.dart
diff --git a/sdk/lib/_internal/compiler/implementation/lib/isolate_patch.dart b/sdk/lib/_internal/compiler/implementation/lib/isolate_patch.dart
index 12b5e0c849bb6b81c0120b611fc437f175e4f490..1c9d772602105508712e858586a4653910b4946b 100644
--- a/sdk/lib/_internal/compiler/implementation/lib/isolate_patch.dart
+++ b/sdk/lib/_internal/compiler/implementation/lib/isolate_patch.dart
@@ -85,7 +85,7 @@ void startRootIsolate(entry) {
 // TODO(eub, sigmund): move the "manager" to be entirely in JS.
 // Running any Dart code outside the context of an isolate gives it
 // the change to break the isolate abstraction.
-_Manager get _globalState => JS("Object", r"$globalState");
+_Manager get _globalState => JS("_Manager", r"$globalState");
 set _globalState(_Manager val) {
   JS("void", r"$globalState = #", val);
 }
@@ -1015,7 +1015,7 @@ class _JsVisitedMap implements _MessageTraverserVisitedMap {
   }
 
   _getAttachedInfo(var o) {
-    return JS("Object", "#['__MessageTraverser__attached_info__']", o);
+    return JS("", "#['__MessageTraverser__attached_info__']", o);
   }
 }