Merge "Add documentation for LayoutParams.preferredRefreshRate" into tm-dev am: 336fcab7 am: b47c1c29 am: 3446d726 am: 2a17aab7

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17955874



Change-Id: Id6a5b45345a09ec23f64aa68f888cde723d4537f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>