Merge "Update letterbox restart dialog style to match other Android U dialogs"...

Merge "Update letterbox restart dialog style to match other Android U dialogs" into udc-dev am: 565b8127 am: 287b71d8 am: a25c6d1c

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23561836



Change-Id: Ic5146bbe19a04f7c2d1b0d923c95982abe23ad85
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>