Fixed indexOutOfBoundsException in WindowManager

Problem was introduced in ag/1395371 where we were looking through the
wrong list for the wallpaper. We need to look through the DisplayContent
window list which is windowList and not the WindowToken list which is windows.

Bug: 31234488
Change-Id: If8b3d4c00f268525132a0c452a0225c90c9f02b1
1 file changed