Merge "[1/n] Move Letterbox education dialog classes" into tm-qpr-dev am: 812e3291 am: 04378e03 am: 92a72a71 am: 2cb2f422

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21911723



Change-Id: Iba798ad318664ef5bcac98ff4b07a0cb39706267
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>