Revert "Stop timer when notification isn't visible"

This reverts commit 3c4a8e48d404649bd03ee8e6e377dcf9a65afee9.

Reason for revert: NPE errors
Fixes: b/138697134

Change-Id: Ic89eb58cd68485dcc5e7c5a3ef48d7ed79c303ca
2 files changed