Merge "Add support for floating IME to split-screen" into rvc-dev am: 3d4bab48 am: d395f428 am: e3e2ed2b

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/11932146

Change-Id: I733831cf521d55e956b9d139e24ecb631692e928