Bug #6642475
When expanding the status bar, create one layer per notification instead of
a single giant layer for the pile of notifications. This prevents layer
creation failure when the total height of the notifications is larger
than the maximum allowed texture size in OpenGL ES 2.0.
This change only enables layers on notifications that will be visible
once the notification area is fully expanded.
Change-Id: I3c791a66cf5ac0973f3a65cfcd84b95209d580f3
54ab347fdd