[V8] Unify get function name for debugging purpose

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 5d4c9c0c415ac558747dfa55b25b19a02c9187b4..b60c4ef0132dbe7cf7c5ea68a764c39c2ec60e65 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -4443,6 +4443,18 @@ Local<Value> Function::GetInferredName() const {
 }
 
 
+Local<Value> Function::GetDebugName() const {
+  auto self = Utils::OpenHandle(this);
+  if (!self->IsJSFunction()) {
+    return ToApiHandle<Primitive>(
+        self->GetIsolate()->factory()->undefined_value());
+  }
+  auto func = i::Handle<i::JSFunction>::cast(self);
+  i::Handle<i::String> name = i::JSFunction::GetDebugName(func);
+  return Utils::ToLocal(i::Handle<i::Object>(*name, name->GetIsolate()));
+}
+
+
 Local<Value> Function::GetDisplayName() const {
   i::Isolate* isolate = Utils::OpenHandle(this)->GetIsolate();
   ENTER_V8(isolate);