Merge "Show correct last notification time for grouped notifications" into...

Merge "Show correct last notification time for grouped notifications" into udc-dev am: f32a80bf am: fdad6d03

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21609427



Change-Id: I8a00b5755678f3981eba1fed28d2841539e8426c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>