Define a resource of Service module, But 'access callback' cannot work
Is your access callback in the same file? If not, you'd have to add: "access callback file" to your definition, and point to it.

I'd also clear cache within Drupal, as I've seen drush cc all not always clear all caches.

Also, I'd name-space your access callback function, as it could be conflicting with something else in the system. _message_access is a pretty generic name. You should rename it to: _baidu_push_services_message_access().

Otherwise, your syntax looks correct.

Or, if you solved your issue, perhaps post it in here, to help others.