Hide the CC button for <audio> with <track>s

LayoutTests/media/video-test.js

Index: LayoutTests/media/video-test.js
diff --git a/LayoutTests/media/video-test.js b/LayoutTests/media/video-test.js
index 986f000d2ac50b776497f0eeaeb39b48105f2817..df1287048719d07bb4c0804ba55434afef649d5b 100644
--- a/LayoutTests/media/video-test.js
+++ b/LayoutTests/media/video-test.js
@@ -46,6 +46,11 @@ function findMediaElement()
         video = document.getElementsByTagName('video')[0];
         if (video)
             mediaElement = video;
+        else {
+            audio = document.getElementsByTagName('audio')[0];
+            if (audio)
+                mediaElement = audio;
+        }
     } catch (ex) { }
 }