Improve caption button behavior for video player.

third_party/WebKit/LayoutTests/media/video-controls-captions-on-off.html

Index: third_party/WebKit/LayoutTests/media/video-controls-captions-on-off.html
diff --git a/third_party/WebKit/LayoutTests/media/video-controls-captions-on-off.html b/third_party/WebKit/LayoutTests/media/video-controls-captions-on-off.html
index 383bc912e7cf1928fc84316774b429e56f407222..1e28eb56b3056b06bc842df0cb6119cc84211eed 100644
--- a/third_party/WebKit/LayoutTests/media/video-controls-captions-on-off.html
+++ b/third_party/WebKit/LayoutTests/media/video-controls-captions-on-off.html
@@ -11,16 +11,17 @@ async_test(function(t) {
     var video = document.querySelector("video");
 
     video.oncanplaythrough = t.step_func_done(function() {
-        var track = video.addTextTrack("captions");
+        var track1 = video.addTextTrack("captions");
+        var track2 = video.addTextTrack("captions");
 
         for (var i = 0; i < text.length; i++) {
-            var cue = new VTTCue(0, 120, text[i]);
-            track.addCue(cue);
+            track1.addCue(new VTTCue(0, 120, text[i]));
+            track2.addCue(new VTTCue(0, 120, text[i]));
         }
         assert_true(isClosedCaptionsButtonVisible(video));
 
         // The captions track should be listed in textTracks, but not yet loaded.
-        assert_equals(video.textTracks.length, 1);
+        assert_equals(video.textTracks.length, 2);
         assert_equals(video.textTracks[0].mode, "hidden");
         checkCaptionsHidden();