Use symbols instead of hidden properties for i18n markers.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 78c45b0e2210b30fdb9fdf0485c48f63204d66a3..3f63dd198356b86ef31c9c092a82b35a54baaa90 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -2868,18 +2868,10 @@ void Heap::CreateInitialObjects() {
   // Number of queued microtasks stored in Isolate::pending_microtask_count().
   set_microtask_queue(empty_fixed_array());
 
-  set_detailed_stack_trace_symbol(*factory->NewPrivateOwnSymbol());
-  set_elements_transition_symbol(*factory->NewPrivateOwnSymbol());
-  set_frozen_symbol(*factory->NewPrivateOwnSymbol());
-  set_megamorphic_symbol(*factory->NewPrivateOwnSymbol());
-  set_premonomorphic_symbol(*factory->NewPrivateOwnSymbol());
-  set_generic_symbol(*factory->NewPrivateOwnSymbol());
-  set_nonexistent_symbol(*factory->NewPrivateOwnSymbol());
-  set_normal_ic_symbol(*factory->NewPrivateOwnSymbol());
-  set_observed_symbol(*factory->NewPrivateOwnSymbol());
-  set_stack_trace_symbol(*factory->NewPrivateOwnSymbol());
-  set_uninitialized_symbol(*factory->NewPrivateOwnSymbol());
-  set_home_object_symbol(*factory->NewPrivateOwnSymbol());
+#define SYMBOL_INIT(name) \
+  roots_[k##name##RootIndex] = *factory->NewPrivateOwnSymbol();
+  PRIVATE_SYMBOL_LIST(SYMBOL_INIT)
+#undef SYMBOL_INIT
 
   Handle<SeededNumberDictionary> slow_element_dictionary =
       SeededNumberDictionary::New(isolate(), 0, TENURED);