base

Improve the reboot-to-recovery dialogs

To address the UX comments, this CL modifies the dialogs when the
device is rebooted to install an update or to perform factory data
reset.

Bug: 20949086
(cherry picked from commit 81dce6631396012e8b722bbed6d003f584800ae1)
Change-Id: I6d0cbbbaf184806366c6581c1c2e7dbcc5d89a17