b/5456741 Fix date updates when leaving edit event. Do not merge

This stashes the flags used to create the date header and then
updates it when the main activity returns so that we update even
if we miss the event telling us to update.

Cherry pick of https://android-git.corp.google.com/g/#/c/142169/
from Master.

Change-Id: I73b8a6414184e50cc6cd313b039b4137b9a84d2f