Revert "SystemUI: Fix potential NPE"

This reverts commit 45d7011c7f544ef963adfd6e13ece816f16471e7.
Revert "HeadsUp: Option to launch in floating window [1/2]"

This reverts commit 335c504dd491351581f6bfc8f01752af4ca38c96.

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

Change-Id: I13e62d3f925b64a94d15b0151b94a7b102ad4355