Add ability to hide DisplayAreas through WindowOrganizer

We add a separate code path to handle DisplayAreas specific transactions
and ability to hide DisplayAreas by applying hidden flag to all tasks
of specific DisplayAreas.

Test: atest WmTests:WindowOrganizerTests#testDisplayAreaHiddenTransaction
Bug: 152116327
Change-Id: Iec4315da27f6f7ffe56d8fee5141dc9d8dfb3560
(cherry picked from commit 0be8abd855295af6ec67b51c3e74dbc12811b06f)
2 files changed