Merge "Restore trimMemory behaviour from T" into udc-dev am: 90c9dbf7b9

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24733945

Change-Id: Ifabacd5719be5ec72ee9cbebb8729fbfbc76d000
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>