question: public void updateVisiblityValue ( int referenceIndex ) { mCachedVisibleArea = mLayoutTab . computeVisibleArea ( ) ; mCachedIndexDistance = Math . abs ( mIndex - referenceIndex ) ; mOrderSortingValue = computeOrderSortingValue ( mCachedIndexDistance , mCacheStackVisibility ) ; mVisiblitySortingValue = computeVisibilitySortingValue ( mCachedVisibleArea , mOrderSortingValue , mCacheStackVisibility ) ; }
target:  Updates the cached visible area value to be used to sort tabs by visibility.