Merge "Make BackEvent#getTouchX and BackEvent#getTouchY floats." into tm-dev am: e16244c3

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



Change-Id: I86e622e8603d4fca97192b0a5f66834be6d0f42d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>