Bug 1093835 - Turn unnecessary array.map to array.forEach in pc.js. r=jib

MozReview-Commit-ID: 1oqXtncwUQ1

--HG--
extra : rebase_source : 2aad2e3c19c664ba61a26beb43ef75ee5f05bd03

dom/media/tests/mochitest/pc.js

@@ -1004,13 +1004,13 @@ PeerConnectionWrapper.prototype = {
     return Promise.all(constraintsList.map(constraints => {
       return getUserMedia(constraints).then(stream => {
         if (constraints.audio) {
-          stream.getAudioTracks().map(track => {
+          stream.getAudioTracks().forEach(track => {
             info(this + " gUM local stream " + stream.id +
               " with audio track " + track.id);
           });
         }
         if (constraints.video) {
-          stream.getVideoTracks().map(track => {
+          stream.getVideoTracks().forEach(track => {
             info(this + " gUM local stream " + stream.id +
               " with video track " + track.id);
           });