diff --git a/dom/media/test/test_texttrack.html b/dom/media/test/test_texttrack.html
index a89921d27166..58acedbf20bc 100644
--- a/dom/media/test/test_texttrack.html
+++ b/dom/media/test/test_texttrack.html
@@ -7,110 +7,113 @@
 </head>
 <body>
 <script type="text/javascript">
-SimpleTest.waitForExplicitFinish();
-SpecialPowers.pushPrefEnv({"set": [["media.webvtt.regions.enabled", true]]},
-  function() {
-    var video = document.createElement("video");
 
-    isnot(video.textTracks, undefined, "HTMLMediaElement::TextTrack() property should be available.")
+function runTest() {
+  var video = document.createElement("video");
 
-    var trackList = video.textTracks;
-    is(trackList.length, 0, "Length should be 0.");
+  isnot(video.textTracks, undefined, "HTMLMediaElement::TextTrack() property should be available.")
 
-    ok(typeof video.addTextTrack == "function", "HTMLMediaElement::AddTextTrack() function should be available.")
-    video.addTextTrack("subtitles", "third", "en-CA");
-    is(trackList.length, 1, "Length should be 1.");
+  var trackList = video.textTracks;
+  is(trackList.length, 0, "Length should be 0.");
 
-    var textTrack = video.textTracks[0];
-    is(textTrack.label, "third", "Label should be set to third.");
-    is(textTrack.language, "en-CA", "Language should be en-CA.");
-    is(textTrack.kind, "subtitles", "Default kind should be subtitles.");
-    is(textTrack.mode, "hidden", "Default mode should be hidden.");
+  ok(typeof video.addTextTrack == "function", "HTMLMediaElement::AddTextTrack() function should be available.")
+  video.addTextTrack("subtitles", "third", "en-CA");
+  is(trackList.length, 1, "Length should be 1.");
 
-    // Mode should not allow a bogus value.
-    textTrack.mode = 'bogus';
-    is(textTrack.mode, 'hidden', "Mode should be not allow a bogus value.");
+  var textTrack = video.textTracks[0];
+  is(textTrack.label, "third", "Label should be set to third.");
+  is(textTrack.language, "en-CA", "Language should be en-CA.");
+  is(textTrack.kind, "subtitles", "Default kind should be subtitles.");
+  is(textTrack.mode, "hidden", "Default mode should be hidden.");
 
-    // Should allow all these values for mode.
-    checkMode("showing", "Mode should allow \"showing\"");
-    checkMode("disabled", "Mode should allow \"disabled\"");
-    checkMode("hidden", "Mode should allow \"hidden\"");
+  // Mode should not allow a bogus value.
+  textTrack.mode = 'bogus';
+  is(textTrack.mode, 'hidden', "Mode should be not allow a bogus value.");
 
-    // All below are read-only properties and so should not allow setting.
-    textTrack.label = "French subtitles";
-    is(textTrack.label, "third", "Label is read-only so should still be \"label\".");
+  // Should allow all these values for mode.
+  checkMode("showing", "Mode should allow \"showing\"");
+  checkMode("disabled", "Mode should allow \"disabled\"");
+  checkMode("hidden", "Mode should allow \"hidden\"");
 
-    textTrack.language = "en";
-    is(textTrack.language, "en-CA", "Language is read-only so should still be \"en-CA\".");
+  // All below are read-only properties and so should not allow setting.
+  textTrack.label = "French subtitles";
+  is(textTrack.label, "third", "Label is read-only so should still be \"label\".");
 
-    textTrack.kind = "captions";
-    is(textTrack.kind, "subtitles", "Kind is read-only so should still be \"subtitles\"");
+  textTrack.language = "en";
+  is(textTrack.language, "en-CA", "Language is read-only so should still be \"en-CA\".");
 
-    function checkMode(value, message) {
-      textTrack.mode = value;
-      is(textTrack.mode, value, message);
+  textTrack.kind = "captions";
+  is(textTrack.kind, "subtitles", "Kind is read-only so should still be \"subtitles\"");
+
+  function checkMode(value, message) {
+    textTrack.mode = value;
+    is(textTrack.mode, value, message);
+  }
+
+  // Insert some tracks in an order that is not sorted, we will test if they
+  // are sorted later.
+  var trackOne = document.createElement("track");
+  trackOne.label = "first";
+  trackOne.src = "basic.vtt";
+  trackOne.default = true;
+  trackOne.id = "2";
+  video.appendChild(trackOne);
+
+  video.addTextTrack("subtitles", "fourth", "en-CA");
+
+  var trackTwo = document.createElement("track");
+  trackTwo.label = "second";
+  trackTwo.src = "basic.vtt";
+  trackTwo.default = true;
+  video.appendChild(trackTwo);
+
+  video.src = "seek.webm";
+  video.preload = "metadata";
+
+  document.appendChild(video);
+
+  video.addEventListener("loadedmetadata", function run_tests() {
+    // Re-que run_tests() at the end of the event loop until the track
+    // element has loaded its data.
+    if (trackOne.readyState == 1 || trackTwo.readyState == 1) {
+      setTimeout(run_tests, 0);
+      return;
     }
+    is(trackOne.readyState, 2, "First Track::ReadyState should be set to LOADED.");
+    is(trackTwo.readyState, 2, "Second Track::ReadyState should be set to LOADED.");
 
-    // Insert some tracks in an order that is not sorted, we will test if they
-    // are sorted later.
-    var trackOne = document.createElement("track");
-    trackOne.label = "first";
-    trackOne.src = "basic.vtt";
-    trackOne.default = true;
-    trackOne.id = "2";
-    video.appendChild(trackOne);
-
-    video.addTextTrack("subtitles", "fourth", "en-CA");
-
-    var trackTwo = document.createElement("track");
-    trackTwo.label = "second";
-    trackTwo.src = "basic.vtt";
-    trackTwo.default = true;
-    video.appendChild(trackTwo);
-
-    video.src = "seek.webm";
-    video.preload = "metadata";
-
-    document.appendChild(video);
-
-    video.addEventListener("loadedmetadata", function run_tests() {
-      // Re-que run_tests() at the end of the event loop until the track
-      // element has loaded its data.
-      if (trackOne.readyState == 1 || trackTwo.readyState == 1) {
-        setTimeout(run_tests, 0);
-        return;
+    // We're testing two things here, firstly that tracks created from a track
+    // element have a default mode 'disabled' and tracks created with the
+    // 'addTextTrack' method have a default mode of 'hidden'.
+    // Secondly we're testing that the tracks are sorted properly.
+    // For the tracks to be sorted the first two tracks, added through a
+    // TrackElement, must occupy the first two indexes in their TrackElement
+    // tree order. The second two tracks, added through the 'addTextTrack'
+    // method, will occupy the last two indexes in the order that they were
+    // added in.
+    var trackData = [
+      { label: "first", mode: "showing", id: "2" },
+      { label: "second", mode: "disabled", id: "" },
+      { label: "third", mode: "hidden", id: "" },
+      { label: "fourth", mode: "hidden", id: "" }
+    ];
+    is(video.textTracks.length, trackData.length, "TextTracks length should be " + trackData.length);
+    for (var i = 0; i < trackData.length; i++) {
+      var track = video.textTracks[i];
+      isnot(track, null, "Video should have a text track at index " + i);
+      var info = trackData[i];
+      for (var key in info) {
+        is(track[key], info[key], "Track at index " + i + " should have a '" + key + "'' property " +
+                                  "with a value of '" + info[key] + "'.");
       }
-      is(trackOne.readyState, 2, "First Track::ReadyState should be set to LOADED.");
-      is(trackTwo.readyState, 2, "Second Track::ReadyState should be set to LOADED.");
+    }
+    SimpleTest.finish();
+  });
+}
+
+SimpleTest.waitForExplicitFinish();
+onload = runTest;
 
-      // We're testing two things here, firstly that tracks created from a track
-      // element have a default mode 'disabled' and tracks created with the
-      // 'addTextTrack' method have a default mode of 'hidden'.
-      // Secondly we're testing that the tracks are sorted properly.
-      // For the tracks to be sorted the first two tracks, added through a
-      // TrackElement, must occupy the first two indexes in their TrackElement
-      // tree order. The second two tracks, added through the 'addTextTrack'
-      // method, will occupy the last two indexes in the order that they were
-      // added in.
-      var trackData = [
-        { label: "first", mode: "showing", id: "2" },
-        { label: "second", mode: "disabled", id: "" },
-        { label: "third", mode: "hidden", id: "" },
-        { label: "fourth", mode: "hidden", id: "" }
-      ];
-      is(video.textTracks.length, trackData.length, "TextTracks length should be " + trackData.length);
-      for (var i = 0; i < trackData.length; i++) {
-        var track = video.textTracks[i];
-        isnot(track, null, "Video should have a text track at index " + i);
-        var info = trackData[i];
-        for (var key in info) {
-          is(track[key], info[key], "Track at index " + i + " should have a '" + key + "'' property " +
-                                    "with a value of '" + info[key] + "'.");
-        }
-      }
-      SimpleTest.finish();
-    });
-});
 </script>
 </body>
 </html>
diff --git a/dom/media/test/test_texttrack_moz.html b/dom/media/test/test_texttrack_moz.html
index 5d7729e261d4..06e59e0753b2 100644
--- a/dom/media/test/test_texttrack_moz.html
+++ b/dom/media/test/test_texttrack_moz.html
@@ -7,50 +7,52 @@
 </head>
 <body>
 <script type="text/javascript">
-  SimpleTest.waitForExplicitFinish();
-  SpecialPowers.pushPrefEnv({"set": [["media.webvtt.regions.enabled", true]]},
-    function() {
-      var video = document.createElement("video");
 
-      // Check if adding a text track manually sets the TextTrackList correctly.
+function runTest() {
+  var video = document.createElement("video");
 
-      // HTMLTrackElement.textTrackList is an extension available only to
-      // privileged code, so we need to access it through the SpecialPowers
-      // object.
-      video.addTextTrack("subtitles", "", "");
-      is(SpecialPowers.unwrap(SpecialPowers.wrap(video.textTracks[0]).textTrackList),
-          video.textTracks,
-          "The Track's TextTrackList should be the Video's TextTrackList.");
+  // Check if adding a text track manually sets the TextTrackList correctly.
+
+  // HTMLTrackElement.textTrackList is an extension available only to
+  // privileged code, so we need to access it through the SpecialPowers
+  // object.
+  video.addTextTrack("subtitles", "", "");
+  is(SpecialPowers.unwrap(SpecialPowers.wrap(video.textTracks[0]).textTrackList),
+      video.textTracks,
+      "The Track's TextTrackList should be the Video's TextTrackList.");
 
 
-      // Check if loading a Track via a TrackElement sets the TextTrackList correctly.
-      video.src = "seek.webm";
-      video.preload = "auto";
+  // Check if loading a Track via a TrackElement sets the TextTrackList correctly.
+  video.src = "seek.webm";
+  video.preload = "auto";
 
-      var trackElement = document.createElement("track");
-      trackElement.src = "basic.vtt";
-      trackElement.kind = "subtitles";
+  var trackElement = document.createElement("track");
+  trackElement.src = "basic.vtt";
+  trackElement.kind = "subtitles";
 
-      video.appendChild(trackElement);
-      document.appendChild(video);
+  video.appendChild(trackElement);
+  document.appendChild(video);
 
-      video.addEventListener("loadedmetadata", function run_tests() {
-        // Re-que run_tests() at the end of the event loop until the track
-        // element has loaded its data.
-        if (trackElement.readyState == HTMLTrackElement.LOADING) {
-          setTimeout(run_tests, 0);
-          return;
-        }
-        is(trackElement.readyState, HTMLTrackElement.LOADED,
-            "Track::ReadyState should be set to LOADED.");
-        is(SpecialPowers.unwrap(SpecialPowers.wrap(trackElement.track).textTrackList),
-           video.textTracks,
-           "TrackElement's Track's TextTrackList should be the Video's TextTrackList.");
-
-        SimpleTest.finish();
-      });
+  video.addEventListener("loadedmetadata", function run_tests() {
+    // Re-que run_tests() at the end of the event loop until the track
+    // element has loaded its data.
+    if (trackElement.readyState == HTMLTrackElement.LOADING) {
+      setTimeout(run_tests, 0);
+      return;
     }
-  );
+    is(trackElement.readyState, HTMLTrackElement.LOADED,
+        "Track::ReadyState should be set to LOADED.");
+    is(SpecialPowers.unwrap(SpecialPowers.wrap(trackElement.track).textTrackList),
+       video.textTracks,
+       "TrackElement's Track's TextTrackList should be the Video's TextTrackList.");
+
+    SimpleTest.finish();
+  });
+}
+
+SimpleTest.waitForExplicitFinish();
+onload = runTest;
+
 </script>
 </body>
 </html>
diff --git a/dom/media/test/test_trackelementevent.html b/dom/media/test/test_trackelementevent.html
index 8255912ea725..7a0462b1b69f 100644
--- a/dom/media/test/test_trackelementevent.html
+++ b/dom/media/test/test_trackelementevent.html
@@ -7,56 +7,58 @@
 </head>
 <body>
 <script type="text/javascript">
-SimpleTest.waitForExplicitFinish();
-SpecialPowers.pushPrefEnv({"set": [["media.webvtt.regions.enabled", true]]},
-  function() {
-    var video = document.createElement("video");
-    video.src = "seek.webm";
-    video.preload = "auto";
 
-    var trackOne = document.createElement("track");
-    trackOne.src = "basic.vtt";
-    trackOne.kind = "subtitles";
+function runTest() {
+  var video = document.createElement("video");
+  video.src = "seek.webm";
+  video.preload = "auto";
 
-    var trackTwo = document.createElement("track");
-    trackTwo.src = "bad-signature.vtt";
-    trackTwo.kind = "captions";
+  var trackOne = document.createElement("track");
+  trackOne.src = "basic.vtt";
+  trackOne.kind = "subtitles";
 
-    var trackThree = document.createElement("track");
-    trackThree.src = "bad.vtt";
-    trackThree.kind = "chapters";
+  var trackTwo = document.createElement("track");
+  trackTwo.src = "bad-signature.vtt";
+  trackTwo.kind = "captions";
 
-    var events = 0;
-    function trackOneEvent() {
-      ok(true, "A load event for trackOne should have happened.");
-      events++ && events == 3 && SimpleTest.finish();
-    }
-    function trackTwoEvent() {
-      ok(true, "An error event for trackTwo should have happened.");
-      events++ && events == 3 && SimpleTest.finish();
-    }
-    function trackThreeEvent() {
-      ok(true, "An error event for trackThree should have happened.");
-      events++ && events == 3 && SimpleTest.finish();
-    }
+  var trackThree = document.createElement("track");
+  trackThree.src = "bad.vtt";
+  trackThree.kind = "chapters";
 
-    function shouldNotBeCalled() {
-      ok(false, "Event should not have been called.");
-    }
-
-    trackOne.addEventListener("load", trackOneEvent);
-    trackOne.addEventListener("error", shouldNotBeCalled)
-    trackTwo.addEventListener("load", shouldNotBeCalled);
-    trackTwo.addEventListener("error", trackTwoEvent);
-    trackThree.addEventListener("load", shouldNotBeCalled);
-    trackThree.addEventListener("error", trackThreeEvent);
-
-    document.appendChild(video);
-    video.appendChild(trackOne);
-    video.appendChild(trackTwo);
-    video.appendChild(trackThree);
+  var events = 0;
+  function trackOneEvent() {
+    ok(true, "A load event for trackOne should have happened.");
+    events++ && events == 3 && SimpleTest.finish();
   }
-);
+  function trackTwoEvent() {
+    ok(true, "An error event for trackTwo should have happened.");
+    events++ && events == 3 && SimpleTest.finish();
+  }
+  function trackThreeEvent() {
+    ok(true, "An error event for trackThree should have happened.");
+    events++ && events == 3 && SimpleTest.finish();
+  }
+
+  function shouldNotBeCalled() {
+    ok(false, "Event should not have been called.");
+  }
+
+  trackOne.addEventListener("load", trackOneEvent);
+  trackOne.addEventListener("error", shouldNotBeCalled)
+  trackTwo.addEventListener("load", shouldNotBeCalled);
+  trackTwo.addEventListener("error", trackTwoEvent);
+  trackThree.addEventListener("load", shouldNotBeCalled);
+  trackThree.addEventListener("error", trackThreeEvent);
+
+  document.appendChild(video);
+  video.appendChild(trackOne);
+  video.appendChild(trackTwo);
+  video.appendChild(trackThree);
+}
+
+SimpleTest.waitForExplicitFinish();
+onload = runTest;
+
 </script>
 </body>
 </html>
