Implement smooth bootup

We copy the /dev/fb0 contents on boot.

BUG=chrome-os-partner:11609
TEST=by hand

Change-Id: I4a8c6158c3c671fe9cf93d02031d98bd4b304b93
Reviewed-on: https://gerrit.chromium.org/gerrit/28460
Tested-by: Stéphane Marchesin <marcheu@chromium.org>
Reviewed-by: Anush Elangovan <anush@google.com>
Commit-Ready: Stéphane Marchesin <marcheu@chromium.org>
3 files changed