cros: Update multiprofile flag message.

BUG=338941
R=dpolukhin@chromium.org

Review URL: https://codereview.chromium.org/178653003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253083 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253083