code: function mouseup(inEvent) {
    if (!this.isEventSimulatedFromTouch_(inEvent)) {
      const p = this.pointerMap[POINTER_ID.toString()];
  
      if (p && p.button === inEvent.button) {
        const e = prepareEvent(inEvent, this.dispatcher);
        this.dispatcher.up(e, inEvent);
        this.cleanupMouse();
      }
    }
  }
docs: Handler for `mouseup`.
  
  @this {MouseSource}
  @param {MouseEvent} inEvent The in event.