Bug 448925 - Too many call to method Grid.indexOf

Grid.indexOf was replaced with GridItem.getRowIndex.
GridItem.getRowIndex invoke Grid.indexOf if needed.
Grid.indexOf method should be package.

Change-Id: I8d8457455b8be3c32aab85a08f3b49238690ddcb
Signed-off-by: mpaturzo <caosmpz@yahoo.it>