Revert of [ic] Use validity cells to protect keyed element stores against object's prototype chain…

src/builtins/builtins-array.cc

 // Copyright 2016 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.
 
 #include "src/builtins/builtins.h"
 #include "src/builtins/builtins-utils.h"
 
 #include "src/code-factory.h"
 #include "src/contexts.h"
 #include "src/elements.h"
@@ skipping 439 matching lines @@
       // during iteration.
       // This shouldn't happen in anything but pathological cases.
       SetDictionaryMode();
       // Fall-through to dictionary mode.
     }
     DCHECK(!fast_elements());
     Handle<SeededNumberDictionary> dict(
         SeededNumberDictionary::cast(*storage_));
     // The object holding this backing store has just been allocated, so
     // it cannot yet be used as a prototype.
-    Handle<JSObject> not_a_prototype_holder;
-    Handle<SeededNumberDictionary> result = SeededNumberDictionary::AtNumberPut(
-        dict, index, elm, not_a_prototype_holder);
+    Handle<SeededNumberDictionary> result =
+        SeededNumberDictionary::AtNumberPut(dict, index, elm, false);
     if (!result.is_identical_to(dict)) {
       // Dictionary needed to grow.
       clear_storage();
       set_storage(*result);
     }
     return true;
   }
 
   void increase_index_offset(uint32_t delta) {
     if (JSObject::kMaxElementCount - index_offset_ < delta) {
@@ skipping 46 matching lines @@
     Handle<FixedArray> current_storage = storage_fixed_array();
     Handle<SeededNumberDictionary> slow_storage(
         SeededNumberDictionary::New(isolate_, current_storage->length()));
     uint32_t current_length = static_cast<uint32_t>(current_storage->length());
     FOR_WITH_HANDLE_SCOPE(
         isolate_, uint32_t, i = 0, i, i < current_length, i++, {
           Handle<Object> element(current_storage->get(i), isolate_);
           if (!element->IsTheHole(isolate_)) {
             // The object holding this backing store has just been allocated, so
             // it cannot yet be used as a prototype.
-            Handle<JSObject> not_a_prototype_holder;
             Handle<SeededNumberDictionary> new_storage =
                 SeededNumberDictionary::AtNumberPut(slow_storage, i, element,
-                                                    not_a_prototype_holder);
+                                                    false);
             if (!new_storage.is_identical_to(slow_storage)) {
               slow_storage = loop_scope.CloseAndEscape(new_storage);
             }
           }
         });
     clear_storage();
     set_storage(*slow_storage);
     set_fast_elements(false);
   }
 
@@ skipping 2071 matching lines @@
         Runtime::kThrowIncompatibleMethodReceiver, context,
         assembler.HeapConstant(assembler.factory()->NewStringFromAsciiChecked(
             "Array Iterator.prototype.next", TENURED)),
         iterator);
     assembler.Return(result);
   }
 }
 
 }  // namespace internal
 }  // namespace v8