Android : GCM for app-engine on android studio not compiling

I have been migrating my project from Eclipse to Android Studio. For my GCM, my server code is not compiling and the import cannot be found for

import com.google.android.gcm.server.Message;
import com.google.android.gcm.server.Result;
import com.google.android.gcm.server.Sender;

Does anyone know the gradle compile line to include? The docs have no suggestion. They have a suggestion for the client side as

compile "com.google.android.gms:play-services:3.1.+"

I need one for my app-engine server.