WIP: Add Firefox interop tests for different formats.

chrome/test/data/webrtc/video_detector.js

Index: chrome/test/data/webrtc/video_detector.js
diff --git a/chrome/test/data/webrtc/video_detector.js b/chrome/test/data/webrtc/video_detector.js
index 4c966101a78df59e7b195b01d4241f849df9f67b..fb1d5a50deb695a2c3cde67055c383507fb0fc38 100644
--- a/chrome/test/data/webrtc/video_detector.js
+++ b/chrome/test/data/webrtc/video_detector.js
@@ -78,6 +78,31 @@ function isVideoPlaying() {
   returnToTest('video-not-playing');
 }
 
+function checkVideoFormat(format) {
+  var checkFormat = function(response) {
+    var stats = response.result();
+
+    var txVideo = getStatsReport(stats, "ssrc", "googFirsReceived");
+    var rxVideo = getStatsReport(stats, "ssrc", "googFirsSent");
+
+    var txFormat = txVideo.stat("googCodecName");
+    var rxFormat = rxVideo.stat("googCodecName");
+
+    if (txFormat != format) {
+      throw new failTest(
+          "Wrong video tx format " + txFormat + " expected " + format);
+    }
+    if (rxFormat != format) {
+      throw new failTest(
+          "Wrong video rx format " + rxFormat + " expected " + format);
+    }
+
+    returnToTest('ok-correct-format');
+  }
+
+  appController.infoBox_.call_.getPeerConnectionStats(checkFormat);
+}
+
 /**
  * Queries for the stream size (not necessarily the size at which the video tag
  * is rendered).