code: function ProgressService(serviceRegistry, operationsClient, commandRegistry, progressMonitorClass, preferenceService){
  		this._serviceRegistry = serviceRegistry;
  		this._serviceRegistration = serviceRegistry.registerService("orion.page.progress", this); //$NON-NLS-0$ 
  		this._commandRegistry = commandRegistry;
  		this._operationsClient = operationsClient;
  		this._operations = {};
  		this._operationDeferrds = {};
  		this._operationsIndex = 0;
  		this._lastOperation = null;
  		this._lastIconClass = null;
  		this._progressMonitorClass = progressMonitorClass;
  		this._preferenceService = preferenceService;
  	}
docs: Service for tracking operations changes
  @class Service for tracking operations changes
  @name orion.progress.ProgressService
  @param {orion.serviceregistry.ServiceRegistry} serviceRegistry
  @param {orion.operationsclient.OperationsClient} operationsClient