This can happen because when callback is ran after onDestroy.
We call the runnable as part of the cleanup process to avoid
a leak.
Bug: 319162553
Fixes: 405316024
Test: Launch an app, note the two animations are synced
Verified by locally introducing a startDelay (since otherwise it is hard to tell)
Flag: com.android.launcher3.sync_app_launch_with_taskbar_stash
Change-Id: I961b9a185b2751a8a908d1a7b2cbfdb8bfe0b8f9
Jon Miranda
9bf65787e9