Add Smi::Zero and replace all Smi::FromInt(0) calls

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 6bb15d2e268a01eefff367e45a2eee5cdb823f6a..cfab6226de6950836d590e15ef992993191ae814 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -1061,7 +1061,7 @@ void Template::Set(v8::Local<Name> name, v8::Local<Data> value,
   auto value_obj = Utils::OpenHandle(*value);
   CHECK(!value_obj->IsJSReceiver() || value_obj->IsTemplateInfo());
   if (value_obj->IsObjectTemplateInfo()) {
-    templ->set_serial_number(i::Smi::FromInt(0));
+    templ->set_serial_number(i::Smi::kZero);
     if (templ->IsFunctionTemplateInfo()) {
       i::Handle<i::FunctionTemplateInfo>::cast(templ)->set_do_not_cache(true);
     }
@@ -1395,7 +1395,7 @@ 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_data(i::Smi::FromInt(0));
+  obj->set_data(i::Smi::kZero);
   return Utils::ToLocal(obj);
 }