extensions/amp-position-observer/0.1/amp-position-observer.js
/**
   * Dispatches the `scroll` event (at most every animation frame)
   *
   * This event is triggered only when position-observer triggers which is
   * at most every animation frame.
   *
   * @private
   */
Dispatches the `scroll` event (at most every animation frame)
This event is triggered only when position-observer triggers which is
at most every animation frame.

@private
Dispatches the ` scroll ` event ( at most every animation frame ) This event is triggered only when position - observer triggers which is at most every animation frame . @private
triggerScroll_() {
    const name = 'scroll';
    const event = createCustomEvent(this.win, `${TAG}.${name}`,
        {percent: this.scrollProgress_});
    this.action_.trigger(this.element, name, event, ActionTrust.LOW);
  }
triggerScroll_ ( ) { const name = 'scroll' ; const event = createCustomEvent ( this . win , ` ${ TAG } ${ name } ` , { percent : this . scrollProgress_ } ) ; this . action_ . trigger ( this . element , name , event , ActionTrust . LOW ) ; }
Dispatches the `scroll` event (at most every animation frame)
 This event is triggered only when position-observer triggers which is
 at most every animation frame.
Dispatches the ` scroll ` event ( at most every animation frame ) This event is triggered only when position - observer triggers which is at most every animation frame .