- Modify toDart to first do a simple lookup in the appropriate table before going down the templati…

runtime/vm/dart_api_impl.cc

Index: runtime/vm/dart_api_impl.cc
===================================================================
--- runtime/vm/dart_api_impl.cc	(revision 27632)
+++ runtime/vm/dart_api_impl.cc	(working copy)
@@ -124,7 +124,9 @@
 
 FinalizablePersistentHandle* Api::UnwrapAsWeakPersistentHandle(
     Dart_WeakPersistentHandle object) {
-  ASSERT(Isolate::Current()->api_state()->IsValidWeakPersistentHandle(object));
+  ASSERT(Isolate::Current()->api_state()->IsValidWeakPersistentHandle(object) ||
+         Isolate::Current()->api_state()->
+             IsValidPrologueWeakPersistentHandle(object));
   return reinterpret_cast<FinalizablePersistentHandle*>(object);
 }