Protect the emptiness of Array prototype elements with a PropertyCell.

src/heap/heap.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 
 #include "src/allocation.h"
@@ skipping 167 matching lines @@
   V(JSObject, observation_state, ObservationState)                             \
   V(Object, symbol_registry, SymbolRegistry)                                   \
   V(SeededNumberDictionary, empty_slow_element_dictionary,                     \
     EmptySlowElementDictionary)                                                \
   V(FixedArray, materialized_objects, MaterializedObjects)                     \
   V(FixedArray, allocation_sites_scratchpad, AllocationSitesScratchpad)        \
   V(FixedArray, microtask_queue, MicrotaskQueue)                               \
   V(FixedArray, keyed_load_dummy_vector, KeyedLoadDummyVector)                 \
   V(FixedArray, detached_contexts, DetachedContexts)                           \
   V(ArrayList, retained_maps, RetainedMaps)                                    \
-  V(WeakHashTable, weak_object_to_code_table, WeakObjectToCodeTable)
+  V(WeakHashTable, weak_object_to_code_table, WeakObjectToCodeTable)           \
+  V(PropertyCell, array_protector, ArrayProtector)
 
 // Entries in this list are limited to Smis and are not visited during GC.
 #define SMI_ROOT_LIST(V)                                                   \
   V(Smi, stack_limit, StackLimit)                                          \
   V(Smi, real_stack_limit, RealStackLimit)                                 \
   V(Smi, last_script_id, LastScriptId)                                     \
   V(Smi, arguments_adaptor_deopt_pc_offset, ArgumentsAdaptorDeoptPCOffset) \
   V(Smi, construct_stub_deopt_pc_offset, ConstructStubDeoptPCOffset)       \
   V(Smi, getter_stub_deopt_pc_offset, GetterStubDeoptPCOffset)             \
   V(Smi, setter_stub_deopt_pc_offset, SetterStubDeoptPCOffset)
@@ skipping 2437 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_HEAP_H_