Merge "Store desktop tasks per display id" into udc-dev am: 2238fdb8f7 am: 6bf890622c

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22636878

Change-Id: I85456bf0c2b60b480d5957cb695b4e85330c2b60
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>