Merge "Allow IME to register system back callbacks in...

Merge "Allow IME to register system back callbacks in ImeOnBackInvokedDispatcher#switchRootView." into tm-qpr-dev am: 467383f0

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/20874663



Change-Id: I60b4dc86284c54e956c84054cec3d696465eafc8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>