PackageManager: Add optional prelaunch check step

This ability is protected by config overlays.

Change-Id: I0c80bd9ec6bda3d21557aaa9503f05ff86adf434
Support full size application screenshots

Add optional width and height parameters for
ease of capturing entire application screenshots

Change-Id: I6d154f6b33bfb8ec90e3757a40382c1dc6feaad3
Provide non-interactive APIs to BackupManagerService

- Add return codes for backup and restore in FullBackupRestoreObserver
- Add non-interactive backup and restore methods in BackupManagerService
- Add per-file filters for backup in BackupAgent

Change-Id: Ic1dfd5d144507263baad76f7088a52eab2fb283a