ES6 symbols: prevent reflection and proxy APIs from leaking symbols

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 0120bbf546377f79176095ffe5f1199373c0f17a..08298a27f95d2efdd218f75348f41b8d1bdda330 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -1779,6 +1779,10 @@ class ScavengingVisitor : public StaticVisitorBase {
                     &ObjectEvacuationStrategy<POINTER_OBJECT>::
                         template VisitSpecialized<SlicedString::kSize>);
 
+    table_.Register(kVisitSymbol,
+                    &ObjectEvacuationStrategy<POINTER_OBJECT>::
+                        template VisitSpecialized<Symbol::kSize>);
+
     table_.Register(kVisitSharedFunctionInfo,
                     &ObjectEvacuationStrategy<POINTER_OBJECT>::
                         template VisitSpecialized<SharedFunctionInfo::kSize>);