Chrome OS: Remove html-echo from common elements.

html-echo is a legacy element, and is currently used in a single place.
So it's reasonable to move the dependency to that source.

Bug: 926638
Change-Id: I00fdc114dcc80743d4f3b23c8a8055e054cd13ad
Reviewed-on: https://chromium-review.googlesource.com/c/1460130
Reviewed-by: Roman Sorokin [CET] <rsorokin@chromium.org>
Reviewed-by: Jacob Dufault <jdufault@chromium.org>
Commit-Queue: Alexander Alekseev <alemate@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632554}
6 files changed