Revert "Refactor PanelView and NotificationPanelView into Controllers."

Revert "NoticationPanelView now has a controller."

Revert submission 9930899-b141751146-npv-controller

Reason for revert: b/147295216
Reverted Changes:
I9a92cad63: Refactor PanelView and NotificationPanelView into ...
I454bc4790: NoticationPanelView now has a controller.

Change-Id: Iae9db40e9385e1b88bd2f5f162a5f6d53d91878d