Focus Controller - Change focus to a new item.

focusController.js

    /**
    * This method performs a change of focus to the item index
    * @param {int} itemIndex
    */
    this.handleFocusChangeToItem = function (itemIndex) {
        if(currentlyFocusedItem) {
            currentlyFocusedItem.setFocusState(false);
        }

        var focusableItem = this.getFocusableItem(itemIndex);
        focusableItem.setFocusState(true);

        currentlyFocusedItem = focusableItem;
    };