RTL support for setting drawer lock mode at activity startup.

If setDrawerLockMode is called from application code in onCreate or
onResume, at that point DrawerLayout hasn't had its correct layout
direction applied yet.

Instead of mapping four gravities (left / right / start / end) into
two "absolute" ones, keep track of all possible four lock "locations"
and add primary / fallback paths in the getter.

Also properly save and restore the lock modes for all four supported

Bug: 15781469
Change-Id: I38209e6810ae0b79ccbcefdb118f686349c68433
1 file changed