function getCountOfVisibleItemsWithVisibilityTrue(oLastVisibleItem) {
			var iAllItemsBeforeBreak = 0;
			var aLeftItemsWithVisibleTrue = getLeftItemsWithVisibilityTrue.call(this);
			aLeftItemsWithVisibleTrue.forEach(function (item, i) {
				if (item.getDomRef() === oLastVisibleItem) {
					iAllItemsBeforeBreak = i + 1;
					return false;
				}
			});
			return iAllItemsBeforeBreak;
		}
Get a real number of the all items that are not hidden due to overflow (are not on the second row) neither due to API
property's visibility(i.e. visibility is not false).
"Second row" items are the items which are not shown in the parent container due to css overflow:hidden, i.e.
overflowing items.
@param {Object} oLastVisibleItem The last visible item just before the first item that goes into the overflow (second row)
@returns {int} The number of items that are not hidden due to overflow
@private