GitLab

Add the ability to set specific text used in the ListMenuButton content
description.  This will incorporate the specified text in the generated
content description string.

BUG=782375

Change-Id: Ic40f680dc27efa7de52fe8e6aaca0c3ef6330012
Reviewed-on: https://chromium-review.googlesource.com/872258
Commit-Queue: Tommy Nyquist <nyquist@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530333}