add interceptors which do not mask existing properties

src/objects-inl.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.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 5573 matching lines @@
 ACCESSORS(InterceptorInfo, getter, Object, kGetterOffset)
 ACCESSORS(InterceptorInfo, setter, Object, kSetterOffset)
 ACCESSORS(InterceptorInfo, query, Object, kQueryOffset)
 ACCESSORS(InterceptorInfo, deleter, Object, kDeleterOffset)
 ACCESSORS(InterceptorInfo, enumerator, Object, kEnumeratorOffset)
 ACCESSORS(InterceptorInfo, data, Object, kDataOffset)
 SMI_ACCESSORS(InterceptorInfo, flags, kFlagsOffset)
 BOOL_ACCESSORS(InterceptorInfo, flags, can_intercept_symbols,
                kCanInterceptSymbolsBit)
 BOOL_ACCESSORS(InterceptorInfo, flags, all_can_read, kAllCanReadBit)
+BOOL_ACCESSORS(InterceptorInfo, flags, non_masking, kNonMasking)
 
 ACCESSORS(CallHandlerInfo, callback, Object, kCallbackOffset)
 ACCESSORS(CallHandlerInfo, data, Object, kDataOffset)
 
 ACCESSORS(TemplateInfo, tag, Object, kTagOffset)
 ACCESSORS(TemplateInfo, property_list, Object, kPropertyListOffset)
 ACCESSORS(TemplateInfo, property_accessors, Object, kPropertyAccessorsOffset)
 
 ACCESSORS(FunctionTemplateInfo, serial_number, Object, kSerialNumberOffset)
 ACCESSORS(FunctionTemplateInfo, call_code, Object, kCallCodeOffset)
@@ skipping 2051 matching lines @@
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_