- Add different types for persistent and weak persistent handles

runtime/vm/dart.cc

Index: runtime/vm/dart.cc
===================================================================
--- runtime/vm/dart.cc	(revision 22905)
+++ runtime/vm/dart.cc	(working copy)
@@ -128,6 +128,12 @@
     vm_isolate_->heap()->IterateOldObjects(&premarker);
     vm_isolate_->heap()->WriteProtect(true);
   }
+  // There is planned and know asymmetry here: We enter one scope for the VM
+  // isolate so that we can allocate the "persistent" handles for the predefined
+  // API values (such as Dart_True, Dart_False and Dart_Null).
+  Dart_EnterScope();
+  Api::InitHandles();
+
   Isolate::SetCurrent(NULL);  // Unregister the VM isolate from this thread.
   Isolate::SetCreateCallback(create);
   Isolate::SetInterruptCallback(interrupt);