Merge "Letterbox Reacheability Multiplier Persistence" into tm-qpr-dev am: a8117a579f am: 82a3d574a0

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/19429915

Change-Id: I09f187d2620654a68b96f6722abe97ac6ef2c094
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>