Merge "Only check letterbox position in book mode" into tm-qpr-dev am: edc5058b

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22251403



Change-Id: I3cca4c737e4c8b2d6428d1bba451a283012e1bb4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>