Merge "IME animation: hide IME-related navbar icons until perceptible" into rvc-dev am: e658c76b5c am: f771bf5301

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/11837615

Change-Id: I61a0438125d1f628ca228cb21f70a4f327ef8fe0