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: 54bc86dd

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



Change-Id: Ieb52f2d122ec372ac485f8a18b07b0658f524a52
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>