Remove PROHIBITS_OVERWRITING as it is subsumed by non-configurable properties.

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 "v8.h"
 
 #include "accessors.h"
 #include "allocation-site-scopes.h"
 #include "api.h"
 #include "arguments.h"
@@ skipping 6398 matching lines @@
   for (Object* current = this;
        current != *null_value;
        current = JSObject::cast(current)->GetPrototype()) {
     JSReceiver::cast(current)->LookupOwn(name, result, false);
     if (result->IsFound()) return;
   }
   result->NotFound();
 }
 
 
-// Search object and its prototype chain for callback properties.
-void JSObject::LookupCallbackProperty(Handle<Name> name, LookupResult* result) {
-  DisallowHeapAllocation no_gc;
-  Handle<Object> null_value = GetIsolate()->factory()->null_value();
-  for (Object* current = this;
-       current != *null_value && current->IsJSObject();
-       current = JSObject::cast(current)->GetPrototype()) {
-    JSObject::cast(current)->LookupOwnRealNamedProperty(name, result);
-    if (result->IsPropertyCallbacks()) return;
-  }
-  result->NotFound();
-}
-
-
 static bool ContainsOnlyValidKeys(Handle<FixedArray> array) {
   int len = array->length();
   for (int i = 0; i < len; i++) {
     Object* e = array->get(i);
     if (!(e->IsString() || e->IsNumber())) return false;
   }
   return true;
 }
 
 
@@ skipping 364 matching lines @@
   }
 
   Handle<AccessorPair> accessors = CreateAccessorPairFor(object, name);
   accessors->SetComponents(*getter, *setter);
   accessors->set_access_flags(access_control);
 
   SetPropertyCallback(object, name, accessors, attributes);
 }
 
 
-bool JSObject::CanSetCallback(Handle<JSObject> object, Handle<Name> name) {
-  Isolate* isolate = object->GetIsolate();
-  ASSERT(!object->IsAccessCheckNeeded() ||
-         isolate->MayNamedAccess(object, name, v8::ACCESS_SET));
-
-  // Check if there is an API defined callback object which prohibits
-  // callback overwriting in this object or its prototype chain.
-  // This mechanism is needed for instance in a browser setting, where
-  // certain accessors such as window.location should not be allowed
-  // to be overwritten because allowing overwriting could potentially
-  // cause security problems.
-  LookupResult callback_result(isolate);
-  object->LookupCallbackProperty(name, &callback_result);
-  if (callback_result.IsFound()) {
-    Object* callback_obj = callback_result.GetCallbackObject();
-    if (callback_obj->IsAccessorInfo()) {
-      return !AccessorInfo::cast(callback_obj)->prohibits_overwriting();
-    }
-    if (callback_obj->IsAccessorPair()) {
-      return !AccessorPair::cast(callback_obj)->prohibits_overwriting();
-    }
-  }
-  return true;
-}
-
-
 bool Map::DictionaryElementsInPrototypeChainOnly() {
   Heap* heap = GetHeap();
 
   if (IsDictionaryElementsKind(elements_kind())) {
     return false;
   }
 
   for (Object* prototype = this->prototype();
        prototype != heap->null_value();
        prototype = prototype->GetPrototype(GetIsolate())) {
@@ skipping 106 matching lines @@
     return;
   }
 
   // Make sure that the top context does not change when doing callbacks or
   // interceptor calls.
   AssertNoContextChange ncc(isolate);
 
   // Try to flatten before operating on the string.
   if (name->IsString()) name = String::Flatten(Handle<String>::cast(name));
 
-  if (!JSObject::CanSetCallback(object, name)) return;
-
   uint32_t index = 0;
   bool is_element = name->AsArrayIndex(&index);
 
   Handle<Object> old_value = isolate->factory()->the_hole_value();
   bool is_observed = object->map()->is_observed() &&
                      *name != isolate->heap()->hidden_string();
   bool preexists = false;
   if (is_observed) {
     if (is_element) {
       preexists = HasOwnElement(object, index);
@@ skipping 151 matching lines @@
     return SetAccessor(Handle<JSObject>::cast(proto), info);
   }
 
   // Make sure that the top context does not change when doing callbacks or
   // interceptor calls.
   AssertNoContextChange ncc(isolate);
 
   // Try to flatten before operating on the string.
   if (name->IsString()) name = String::Flatten(Handle<String>::cast(name));
 
-  if (!JSObject::CanSetCallback(object, name)) {
-    return factory->undefined_value();
-  }
-
   uint32_t index = 0;
   bool is_element = name->AsArrayIndex(&index);
 
   if (is_element) {
     if (object->IsJSArray()) return factory->undefined_value();
 
     // Accessors overwrite previous callbacks (cf. with getters/setters).
     switch (object->GetElementsKind()) {
       case FAST_SMI_ELEMENTS:
       case FAST_ELEMENTS:
@@ skipping 10140 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal