Merge "Make BackEvent#getTouchX and BackEvent#getTouchY floats." into tm-dev am: e16244c3cd

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17650054

Change-Id: I5676d1ed488ac18712e06b21f5bd3360cfa20378
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>