Floating window: Enable transparent layer

Halo: Re-enable transparent layer

Change-Id: I3af24ed40314ca5edb1e5157c0ad9df8ac89c99f

App sidebar: enable transparent layer for floating apps

+ cleanup

Change-Id: I6ae8209f7d7839c78840e69bc9597d43fbedc790

enable transparent layer on notification long click

Change-Id: I058a19776bd90d964b5d5df4fcf251c784b3ba8c

Conflicts:

	core/java/android/app/LayerActivity.java
	packages/SystemUI/AndroidManifest.xml