Merge "Allow IME to register callbacks with negative priorities." into tm-qpr-dev am: 77bef7e1d5 am: 6eda890a0e

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/20766528

Change-Id: Ic63fcdd5f3f84fb2d21b47abd72b02c3a66bef39
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>