cros: Remove ScreenContext from error screen

Bug: 926511
Change-Id: Ia11b785b453b72e4f009353d7ad7168a471db743
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1444235
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Commit-Queue: Jacob Dufault <jdufault@chromium.org>
Cr-Commit-Position: refs/heads/master@{#639725}
6 files changed