Bug 839106 - Add preferences to control the stun behavior, r=jesup.

dom/media/PeerConnection.js

@@ -255,9 +255,10 @@ PeerConnection.prototype = {
     if (this._win) {
       throw new Error("RTCPeerConnection constructor already called");
     }
-    if (!rtcConfig) {
-      // TODO(jib@mozilla.com): Hardcoded Mozilla server. Final? Bug 807494
-      rtcConfig = { "iceServers": [{ url: "stun:23.21.150.121" }] };
+    if (!rtcConfig ||
+        !Services.prefs.getBoolPref("media.peerconnection.use_document_iceservers")) {
+      rtcConfig = {iceServers:
+        JSON.parse(Services.prefs.getCharPref("media.peerconnection.default_iceservers"))};
     }
     this._mustValidateRTCConfiguration(rtcConfig,
         "RTCPeerConnection constructor passed invalid RTCConfiguration");

modules/libpref/src/init/all.js

@@ -182,6 +182,8 @@ pref("media.gstreamer.enabled", true);
 pref("media.navigator.enabled", true);
 pref("media.peerconnection.enabled", false);
 pref("media.navigator.permission.disabled", false);
+pref("media.peerconnection.default_iceservers", "[{\"url\": \"stun:23.21.150.121\"}]");
+pref("media.peerconnection.use_document_iceservers", true);
 // These values (aec, agc, and noice) are from media/webrtc/trunk/webrtc/common_types.h
 // kXxxUnchanged = 0, kXxxDefault = 1, and higher values are specific to each 
 // setting (for Xxx = Ec, Agc, or Ns).  Defaults are all set to kXxxDefault here.