private synchronized ServiceResourceProvider getServiceResourceProvider() {
    if (serviceResourceProvider == null) {
      serviceResourceProvider = (ServiceResourceProvider) ClusterControllerHelper.
          getClusterController().ensureResourceProvider(Resource.Type.Service);
    }
    return serviceResourceProvider;
  }
Gets an instance of {@link ConfigHelper} for classes which are not
dependency injected.

@return a {@link ConfigHelper} instance.
ambari-server/src/main/java/org/apache/ambari/server/topology/AmbariContext.java