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

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



Change-Id: I0bc58e380dbb3f494d82f452338aa17f5c7cdddd
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>