code: public static void register(Context context, String... senderIds) {
          GCMRegistrar.resetBackoff(context);
          internalRegister(context, senderIds);
      }
docs: Initiate messaging registration for the current application.
  <p>
  The result will be returned as an
  {@link GCMConstants#INTENT_FROM_GCM_REGISTRATION_CALLBACK} intent with
  either a {@link GCMConstants#EXTRA_REGISTRATION_ID} or
  {@link GCMConstants#EXTRA_ERROR}.
  
  @param context application context.
  @param senderIds Google Project ID of the accounts authorized to send
  messages to this application.
  @throws IllegalStateException if device does not have all GCM
  dependencies installed.