code: function handleAriaSize (aVisibleTiles) {
  		var iTilesCount,
  			i,
  			oTile;
  
  		aVisibleTiles = aVisibleTiles || this._getVisibleTiles();
  		iTilesCount = aVisibleTiles.length;
  
  		for (i = 0; i < iTilesCount; i++) {
  			oTile = aVisibleTiles[i];
  			if (oTile._rendered && oTile.getDomRef()) {
  				oTile.getDomRef().setAttribute("aria-setsize", iTilesCount);
  			}
  		}
  	}
docs: Handles the WAI ARIA property aria-setsize after a change in the TileContainer.
  
  @private