For now, don't assume failed-access-check callback to throw.

src/objects.cc

 // Copyright 2013 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/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <sstream>
 
@@ skipping 1053 matching lines @@
 
 Maybe<bool> JSObject::SetPropertyWithFailedAccessCheck(
     LookupIterator* it, Handle<Object> value, ShouldThrow should_throw) {
   Handle<JSObject> checked = it->GetHolder<JSObject>();
   if (AllCanWrite(it)) {
     return SetPropertyWithAccessor(it, value, should_throw);
   }
 
   it->isolate()->ReportFailedAccessCheck(checked);
   RETURN_VALUE_IF_SCHEDULED_EXCEPTION(it->isolate(), Nothing<bool>());
-  UNREACHABLE();
-  it->isolate()->Throw(
-      *it->isolate()->factory()->NewTypeError(MessageTemplate::kNoAccess));
-  return Nothing<bool>();
+  return Just(true);
 }
 
 
 void JSObject::SetNormalizedProperty(Handle<JSObject> object,
                                      Handle<Name> name,
                                      Handle<Object> value,
                                      PropertyDetails details) {
   DCHECK(!object->HasFastProperties());
   if (!name->IsUniqueName()) {
     name = object->GetIsolate()->factory()->InternalizeString(
@@ skipping 16921 matching lines @@
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 
 }  // namespace internal
 }  // namespace v8