AllocationSite objects weakly linked for traversal

src/objects-visiting.cc

Index: src/objects-visiting.cc
diff --git a/src/objects-visiting.cc b/src/objects-visiting.cc
index 6502209798f3d8df94cb4e2bdcc31a775d26cc19..484bb886b347d24bbf5c27f97049ef8bcfe264ec 100644
--- a/src/objects-visiting.cc
+++ b/src/objects-visiting.cc
@@ -182,6 +182,10 @@ StaticVisitorBase::VisitorId StaticVisitorBase::GetVisitorId(
         case NAME##_TYPE:
       STRUCT_LIST(MAKE_STRUCT_CASE)
 #undef MAKE_STRUCT_CASE
+          if (instance_type == ALLOCATION_SITE_TYPE) {
+            return kVisitAllocationSite;
+          }
+
           return GetVisitorIdForSize(kVisitStruct,
                                      kVisitStructGeneric,
                                      instance_size);