Assert that independent handles do not participate in grouping.

src/global-handles.cc

 // Copyright 2009 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 601 matching lines @@
   }
 }
 
 #endif
 
 
 
 void GlobalHandles::AddObjectGroup(Object*** handles,
                                    size_t length,
                                    v8::RetainedObjectInfo* info) {
+#ifdef DEBUG
+  for (size_t i = 0; i < length; ++i) {
+    ASSERT(!Node::FromLocation(handles[i])->independent_);
+  }
+#endif
   if (length == 0) {
     if (info != NULL) info->Dispose();
     return;
   }
   object_groups_.Add(ObjectGroup::New(handles, length, info));
 }
 
 
 void GlobalHandles::AddImplicitReferences(HeapObject** parent,
                                           Object*** children,
                                           size_t length) {
+#ifdef DEBUG
+  ASSERT(!Node::FromLocation(BitCast<Object**>(parent))->independent_);
+  for (size_t i = 0; i < length; ++i) {
+    ASSERT(!Node::FromLocation(children[i])->independent_);
+  }
+#endif
   if (length == 0) return;
   implicit_ref_groups_.Add(ImplicitRefGroup::New(parent, children, length));
 }
 
 
 void GlobalHandles::RemoveObjectGroups() {
   for (int i = 0; i < object_groups_.length(); i++) {
     object_groups_.at(i)->Dispose();
   }
   object_groups_.Clear();
 }
 
 
 void GlobalHandles::RemoveImplicitRefGroups() {
   for (int i = 0; i < implicit_ref_groups_.length(); i++) {
     implicit_ref_groups_.at(i)->Dispose();
   }
   implicit_ref_groups_.Clear();
 }
 
 
 } }  // namespace v8::internal