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: 1f8ec7b0 am: df3cc3d7

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



Change-Id: Ic01ea1c9162d7f3c0fb1ba39c9c03f98a45d7795
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>