[es6] Fix invalid ToString in implementation of ToName.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 02d8d3481f636d0b90702251b59684cde3eb8861..af37cb114d615f7a4a6eb0cd51bce840a9527aa7 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -94,6 +94,16 @@ MaybeHandle<JSReceiver> Object::ToObject(Isolate* isolate,
 
 
 // static
+MaybeHandle<Name> Object::ToName(Isolate* isolate, Handle<Object> input) {
+  ASSIGN_RETURN_ON_EXCEPTION(
+      isolate, input, Object::ToPrimitive(input, ToPrimitiveHint::kString),
+      Name);
+  if (input->IsName()) return Handle<Name>::cast(input);
+  return ToString(isolate, input);
+}
+
+
+// static
 MaybeHandle<Object> Object::ToNumber(Handle<Object> input) {
   while (true) {
     if (input->IsNumber()) {