In the near future, we will be swtiching to PG headlines to generate the
search blurb. As such, we need to replace audio and video links in the
raw data used for headline generation. This also means that we avoid
replacing links each time we need to generate the blurb.
* this mailer needs some more cleanup and specs;
this commit just adds the missing method so the
mailer does not error completely in secure media
environments