Revert "Fill in ActivatableNotificationViewController."

Revert submission 10162577-b147245740-activitable-notif-view-component

Reason for revert: Broken test. http://b/149099968
Reverted Changes:
I153797743: Add new ExpandableNotificationRowController.
If72c1e19a: Fill in ActivatableNotificationViewController.

Change-Id: I523c151ba87d02b16fcecfbe3147bb5f32f388fb
7 files changed