Changed scavenge GC to collect unmodified references

src/global-handles.cc

Index: src/global-handles.cc
diff --git a/src/global-handles.cc b/src/global-handles.cc
index 650999f394c5cc7c2e5397afff53c74e3c186d20..f8299cf86a84b56f93026f1c7ac2cc21d99c306c 100644
--- a/src/global-handles.cc
+++ b/src/global-handles.cc
@@ -687,6 +687,19 @@ void GlobalHandles::IterateNewSpaceWeakIndependentRoots(ObjectVisitor* v) {
 }
 
 
+void GlobalHandles::IterateNewSpaceWeakRoots(ObjectVisitor* v,
+                                             WeakSlotCallback can_skip) {
+  for (int i = 0; i < new_space_nodes_.length(); ++i) {
+    Node* node = new_space_nodes_[i];
+    Object* object = node->object();
+    // If node->location is used instead of &object, import-expando-gc.html
+    // fails
+    if (node->IsWeak() && !can_skip(node->location()))
+      v->VisitPointer(&object);  // node->location());
+  }
+}
+
+
 bool GlobalHandles::IterateObjectGroups(ObjectVisitor* v,
                                         WeakSlotCallbackWithHeap can_skip) {
   ComputeObjectGroupsAndImplicitReferences();