Fixed retrieving non-initialized wallpaper information

When an attempt is made to retrieve wallpaper information such
as getWidthHint during user switching, the wallpaper may be
uninitialized and therefore throw NullPointerException.

Resolved by initializing wallpaper for current active user
if not yet initialized or returning null if applicable.

Change-Id: I1d3931379cbf4ea82cd25bc813898bbe4fb65a67
[1/2] Speed up booting on multicore devices.

1. Add multithreading support to Installer/installd.
2. Parallelize package scanning.
3. Parallelize boot dexopt.

Change-Id: Id42b2bf4a737f93f9ecd9b5819344adbb735f0fb

Conflicts:
	services/java/com/android/server/pm/PackageManagerService.java
Revert "BootMessage: show more info in boot dialog"

This reverts commit b3ed254bbea91d4b021e27671edf7f6827fd667e.

Conflicts:
	services/java/com/android/server/pm/PackageManagerService.java

Change-Id: I9a80e4311115b276d34dfe78dccbaf352526ca30