Bug 1284102 - Switch from mozGUM to mediaDevice.gUM for chrome tests. r=florian

MozReview-Commit-ID: JH2LODA9Rpp

--HG--
extra : rebase_source : 7f314ea1a0153c7354fd4237fa5c4561828a3513

browser/base/content/test/webrtc/get_user_media.html

@@ -35,10 +35,11 @@ function requestDevice(aAudio, aVideo, aShare) {
     opts.fake = true;
   }
 
-  window.navigator.mozGetUserMedia(opts, function(stream) {
+  window.navigator.mediaDevices.getUserMedia(opts)
+    .then(stream => {
       gStream = stream;
       message("ok");
-  }, function(err) { message("error: " + err); });
+    }, err => message("error: " + err));
 }
 message("pending");