Implement immutable prototype chains

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index becc51380f90da75fbaf1e086f0082826b049d97..34f54833746baa3f3cd2a5fa0d18bb4be0d94176 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -1417,7 +1417,7 @@ static Local<ObjectTemplate> ObjectTemplateNew(
   obj->set_serial_number(i::Smi::FromInt(next_serial_number));
   if (!constructor.IsEmpty())
     obj->set_constructor(*Utils::OpenHandle(*constructor));
-  obj->set_internal_field_count(i::Smi::FromInt(0));
+  obj->set_data(i::Smi::FromInt(0));
   return Utils::ToLocal(obj);
 }
 
@@ -1712,7 +1712,7 @@ void ObjectTemplate::SetCallAsFunctionHandler(FunctionCallback callback,
 
 
 int ObjectTemplate::InternalFieldCount() {
-  return i::Smi::cast(Utils::OpenHandle(this)->internal_field_count())->value();
+  return Utils::OpenHandle(this)->internal_field_count();
 }
 
 
@@ -1730,9 +1730,18 @@ void ObjectTemplate::SetInternalFieldCount(int value) {
     // function to do the setting.
     EnsureConstructor(isolate, this);
   }
-  Utils::OpenHandle(this)->set_internal_field_count(i::Smi::FromInt(value));
+  Utils::OpenHandle(this)->set_internal_field_count(value);
 }
 
+bool ObjectTemplate::ImmutableProto() {
+  return Utils::OpenHandle(this)->immutable_proto();
+}
+
+void ObjectTemplate::SetImmutableProto() {
+  i::Isolate* isolate = Utils::OpenHandle(this)->GetIsolate();
+  ENTER_V8(isolate);
+  Utils::OpenHandle(this)->set_immutable_proto(true);
+}
 
 // --- S c r i p t s ---