B2G/gecko/toolkit/content/Task.jsm
/**
 * Executes the specified iterator as a task, and gives access to the promise
 * that is fulfilled when the task terminates.
 */
Executes the specified iterator as a task, and gives access to the promise
that is fulfilled when the task terminates.
Executes the specified iterator as a task and gives access to the promise that is fulfilled when the task terminates .
function TaskImpl(iterator) {
  this.deferred = Promise.defer();
  this._iterator = iterator;
  this._run(true);
}
function TaskImpl ( iterator ) { this . deferred = Promise . defer ( ) ; this . _iterator = iterator ; this . _run ( true ) ; }
Executes the specified iterator as a task, and gives access to the promise
 that is fulfilled when the task terminates.
Executes the specified iterator as a task and gives access to the promise that is fulfilled when the task terminates .