Merge "Add FLAG_IMMUTABLE to PendingIntents" am: a3aa817aa5 am: b119c3792c am: fc609be986 am: 37b0cb3495

Original change: https://android-review.googlesource.com/c/platform/development/+/2229375

Change-Id: Id7f9eb8de9f8de3f221d05ff98f31cf45ba9ce8b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>