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

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



Change-Id: If378e9e798615792efad0c8d52513b32c91da3cb
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>