Fix issue #3083761: windowSoftInputMode="adjustPan" ignored on stingray

The code for the new always-there status bar was a bit too brute-force,
and also impacting things like the IME.  We now implement this by
actually having an explicit concept of "display size" that the status bar
can carve out from everyone else.

Change-Id: I1963d0b07f52e8d8dc3c836227da9bf5d3f2e8b9