[proxies] Make Object.{isFrozen,isSealed} behave correctly for proxies.

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 7279 matching lines @@
               ? no_conf
               : no_conf_no_write;
       DefineOwnProperty(isolate, receiver, key, &desc, THROW_ON_ERROR);
       if (isolate->has_pending_exception()) return Nothing<bool>();
     }
   }
   return Just(true);
 }
 
 
+Maybe<bool> JSReceiver::TestIntegrityLevel(Handle<JSReceiver> object,
+                                           IntegrityLevel level) {
+  DCHECK(level == SEALED || level == FROZEN);
+  Isolate* isolate = object->GetIsolate();
+
+  Maybe<bool> extensible = JSReceiver::IsExtensible(object);
+  MAYBE_RETURN(extensible, Nothing<bool>());
+  if (extensible.FromJust()) return Just(false);
+
+  Handle<FixedArray> keys;
+  ASSIGN_RETURN_ON_EXCEPTION_VALUE(
+      isolate, keys, JSReceiver::OwnPropertyKeys(object), Nothing<bool>());
+
+  for (int i = 0; i < keys->length(); ++i) {
+    Handle<Object> key(keys->get(i), isolate);
+    PropertyDescriptor current_desc;
+    bool owned = JSReceiver::GetOwnPropertyDescriptor(isolate, object, key,
+                                                      &current_desc);
+    if (isolate->has_pending_exception()) return Nothing<bool>();
+    if (owned) {
+      if (current_desc.configurable()) return Just(false);
+      if (level == FROZEN &&
+          PropertyDescriptor::IsDataDescriptor(&current_desc) &&
+          current_desc.writable()) {
+        return Just(false);
+      }
+    }
+  }
+  return Just(true);
+}
+
+
 Maybe<bool> JSReceiver::PreventExtensions(Handle<JSReceiver> object,
                                           ShouldThrow should_throw) {
   if (object->IsJSProxy()) {
     return JSProxy::PreventExtensions(Handle<JSProxy>::cast(object),
                                       should_throw);
   }
   DCHECK(object->IsJSObject());
   return JSObject::PreventExtensions(Handle<JSObject>::cast(object),
                                      should_throw);
 }
@@ skipping 11784 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