[snapshot] optimizing WatchedArrayList snapshot am: d5c4c550 am: 852703f1...

[snapshot] optimizing WatchedArrayList snapshot am: d5c4c550 am: 852703f1 am: dbf7f100 am: 7c68d719

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18185712



Change-Id: I8d612eb55cf8eaa695e365951a6e4d2f03654ad2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>