Merge pull request #14455 from ethantseng/rtsp/bug928332

Bug 928332 - [RTSP][Gaia] Support RTSP in Video apps., r=johnhu
(cherry picked from commit ff703bf2c0baaf06b2b74144bec9b9cc99f22404)
Merge pull request #14593 from huchengtw-moz/video/Bug_928332-v1.3

Merge pull request #14455 from ethantseng/rtsp/bug928332