Throw as per spec when modifying an Array with builtin methods

src/objects.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_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 10166 matching lines @@
   DECL_ACCESSORS(length, Object)
 
   // Overload the length setter to skip write barrier when the length
   // is set to a smi. This matches the set function on FixedArray.
   inline void set_length(Smi* length);
 
   static void JSArrayUpdateLengthFromIndex(Handle<JSArray> array,
                                            uint32_t index,
                                            Handle<Object> value);
 
-  static bool IsReadOnlyLengthDescriptor(Handle<Map> jsarray_map);
+  static bool HasReadOnlyLength(Handle<JSArray> array);
   static bool WouldChangeReadOnlyLength(Handle<JSArray> array, uint32_t index);
   static MaybeHandle<Object> ReadOnlyLengthError(Handle<JSArray> array);
 
+  // TODO(adamk): Remove this method in favor of HasReadOnlyLength().
+  static bool IsReadOnlyLengthDescriptor(Handle<Map> jsarray_map);
+
   // Initialize the array with the given capacity. The function may
   // fail due to out-of-memory situations, but only if the requested
   // capacity is non-zero.
   static void Initialize(Handle<JSArray> array, int capacity, int length = 0);
 
   // Initializes the array to a certain length.
   inline bool AllowsSetElementsLength();
   // Can cause GC.
   MUST_USE_RESULT static MaybeHandle<Object> SetElementsLength(
       Handle<JSArray> array,
@@ skipping 760 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_