Merge "Add documentation for LayoutParams.preferredRefreshRate" into tm-dev am: 336fcab7 am: b217bbb6 am: 2e6ba6fc

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



Change-Id: I791e26c0960b55c1b4d816f59bbb5fac3ce1c7cb
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>