1. The reason is that the screen magnifier computes that the whole
screen is not magnifiable. The miscalculation was caused due to
an incorrect assumption that the non-magnified area is only at
the bottom. In fact, on a phone in landscape the non-magnified
area is both on the right and at the bottom. This change adds
a correct algorithm for computing the magnified region.
2. Increasing the delay for computing the magnified area when the
keyguard goes away to allow all windows hidden by the keyguard
to be shown. In rare occasions the previous delay was not long
enough resulting in a state where the keyboard is considered
a part of the magnified region.
3. Removed some dead code.
bug:7293097
Change-Id: Ic5ff91977df8bcf4afd77071685c3eb20555d4f3