When the drawer is open, hide the icons & toasts.
Move Clear button to the bottom and add DND button.
Change-Id: I8b3253eb8f2ff3b1e11a819d58b202e023f00710
Not yet wired up to FLAG_FULLSCREEN; right now you must
invoke it manually by longpressing on the clock area.
Bug: 2905073
Change-Id: I43a005f2e4c08edb3673aef523bcaa1e088e8a71