[Touchless] Update placeholder text and add special case for first run

Bug: 954529
Change-Id: I9cba7d40d2bc024226274debf1ffc1c5e60b5241
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1574297
Reviewed-by: Matthew Jones <mdjones@chromium.org>
Reviewed-by: Justin DeWitt <dewittj@chromium.org>
Commit-Queue: Brandon Wylie <wylieb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654064}
5 files changed