Add prompt for launching diagnostics

On recovery screen and OS broken screen show a prompt that explains how
to launch diagnostics if diagnostics is enabled.

BUG=b:130244249
TEST=Tested on arcada
BRANCH=sarien
Cq-Depend: chrome-internal:1301017

Change-Id: I79dda12a53f1e7d26449e9cb7e75602a5ed400e7
Signed-off-by: Mathew King <mathewk@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1564828
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
1 file changed