Here's an e-mail (of Jan 2015) from webkit-dev:
from which I can see the work on WebRTC support in WebKit is (was on that date) still in progress. The version of WebKit we've last updated to is of Feb 2014, a year older.
Also, currently we don't even compile the sources related to webrtc. The JavaFX media component (used in WebView to play media content) is based on GStreamer which may be a base for webrtc, however we haven't yet investigated it. (Will it work from scratch, being supported by WebKit, or will we have to add some new glue code b/w WebKit and FX media?).
Please, file a JIRA issue (enhancement).