HALO: show halo button in pie

Change-Id: I858ec08837559f4b2806df0ac68b8a703189b1db
HALO: keep apps in recents

Change-Id: I9ede8a1aba8d6721f077a39a31b6cc5cd8272dc2

Conflicts:
	services/java/com/android/server/am/ActivityRecord.java