Make assertion scopes thread safe.

src/factory.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 458 matching lines @@
       isolate()->heap()->AllocateExternalArray(length,
                                                array_type,
                                                external_pointer,
                                                pretenure),
       ExternalArray);
 }
 
 
 Handle<JSGlobalPropertyCell> Factory::NewJSGlobalPropertyCell(
     Handle<Object> value) {
-  ALLOW_HANDLE_DEREF(isolate(),
-                     "converting a handle into a global property cell");
+  AllowDeferredHandleDereference convert_to_cell;
   CALL_HEAP_FUNCTION(
       isolate(),
       isolate()->heap()->AllocateJSGlobalPropertyCell(*value),
       JSGlobalPropertyCell);
 }
 
 
 Handle<Map> Factory::NewMap(InstanceType type,
                             int instance_size,
                             ElementsKind elements_kind) {
@@ skipping 1065 matching lines @@
   return Handle<Object>::null();
 }
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return value ? true_value() : false_value();
 }
 
 
 } }  // namespace v8::internal