halo: add dropshadow to halo ring drawable

it was not visible on a solid white background

Change-Id: Ib1aeb673f6845a5fc903a38647964de7bdcb7ebd
ActiveDisplay: Remove brightness logic and revert removal of IPowerManager screen state getter

Revert "ActiveDisplay: Remove unnecessary IPowerManager getter for screen state"

This reverts commit e3fa9dd6089f33325766400b93afb1766bf54965.

Change-Id: Ib7a7853d50c798c0af660d62aae0e0aabfccf39d

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/policy/activedisplay/ActiveDisplayView.java