message: refactor(AsyncAction): stop using root
diff: -import { root } from '../util/root';
  import { Action } from './Action';
  import { Subscription } from '../Subscription';
  import { AsyncScheduler } from './AsyncScheduler';
  @@ -69,7 +68,7 @@ export class AsyncAction<T> extends Action<T> {
  }
  protected requestAsyncId(scheduler: AsyncScheduler, id?: any, delay: number = 0): any {
  - return root.setInterval(scheduler.flush.bind(scheduler, this), delay);
  + return setInterval(scheduler.flush.bind(scheduler, this), delay);
  }
  protected recycleAsyncId(scheduler: AsyncScheduler, id: any, delay: number = 0): any {
  @@ -79,7 +78,7 @@ export class AsyncAction<T> extends Action<T> {
  }
  // Otherwise, if the action's delay time is different from the current delay,
  // or the action has been rescheduled before it's executed, clear the interval id
  - return root.clearInterval(id) && undefined || undefined;
  + return clearInterval(id) && undefined || undefined;
  }
  /**
  