Do not wait for first video frame to start playing audio in a MediaStream.

content/test/data/media/getusermedia.html

Index: content/test/data/media/getusermedia.html
diff --git a/content/test/data/media/getusermedia.html b/content/test/data/media/getusermedia.html
index 0e98cc6c110f03b651a4372425d72e3da7ea6a16..474bdad72cf5776fff0edcc2bf84d56b96c975e3 100644
--- a/content/test/data/media/getusermedia.html
+++ b/content/test/data/media/getusermedia.html
@@ -460,8 +460,16 @@
     var detectorFunction = function() {
       var width = videoElement.videoWidth;
       var height = videoElement.videoHeight;
-      if (width == 0 || height == 0)
-        failTest("VideoElement width and height set to 0.");
+      if (width == 0 || height == 0) {
+        if (++attempt > maxAttempts) {
+          clearInterval(detectorInterval);
+          failTest("VideoElement width or height set to 0.");
+        }
+        else {
+          // We have zero size now; give a chance to shape up.
+          return;
+        }
+      }
 
       canvas.width = width;
       canvas.height = height;