[es6] silence access-check failure for well-known symbol 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 1139 matching lines @@
   return ToObject(
       isolate, object, handle(isolate->context()->native_context(), isolate));
 }
 
 
 bool Object::HasSpecificClassOf(String* name) {
   return this->IsJSObject() && (JSObject::cast(this)->class_name() == name);
 }
 
 
+MaybeHandle<Object> Object::GetProperty(LookupIterator* it,
+                                        LanguageMode language_mode) {
+  bool failedAccessCheck = false;
+  MaybeHandle<Object> result =
+      GetPropertyInternal(it, &failedAccessCheck, language_mode);
+  if (failedAccessCheck) return JSObject::GetPropertyWithFailedAccessCheck(it);
+  return result;
+}
+
+
 MaybeHandle<Object> Object::GetProperty(Handle<Object> object,
                                         Handle<Name> name,
                                         LanguageMode language_mode) {
   LookupIterator it(object, name);
   return GetProperty(&it, language_mode);
 }
 
 
+MaybeHandle<Object> Object::GetPropertyOrFallbackValue(
+    Handle<Object> object, Handle<Name> name, Handle<Object> fallbackValue,
+    LanguageMode language_mode) {
+  LookupIterator it(object, name);
+  bool failedAccessCheck = false;
+  MaybeHandle<Object> result =
+      GetPropertyInternal(&it, &failedAccessCheck, language_mode);
+  if (V8_UNLIKELY(failedAccessCheck)) {
+    result = fallbackValue;
+  }
+  return result;
+}
+
+
 MaybeHandle<Object> Object::GetElement(Isolate* isolate, Handle<Object> object,
                                        uint32_t index,
                                        LanguageMode language_mode) {
   LookupIterator it(isolate, object, index);
   return GetProperty(&it, language_mode);
 }
 
 
 Handle<Object> Object::GetPrototypeSkipHiddenPrototypes(
     Isolate* isolate, Handle<Object> receiver) {
@@ skipping 6137 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_