Comment 12 for bug 1151601

Per Youttube ToS (https://www.youtube.com/t/terms accessed 11Jan2015) Section 4.c:

"You agree not to access Content through any technology or means other than the video playback pages of the Service itself, the Embeddable Player, or other explicitly authorized means YouTube may designate."

Per this section, OLP would have to get an exception from Google/Youtube to be able to integrate a youtube downloader into OLP.