Add TODOs to convert from video-test.js to testharness.js

third_party/WebKit/LayoutTests/media/video-controls-in-media-document.html

 <p>Test that controls don't increase the size of the container (i.e. are
 rendered overlapping with the video canvas).<p>
 <script src="media-file.js" type="text/javascript"></script>
+<!-- TODO(philipj): Convert test to testharness.js. crbug.com/588956
+     (Please avoid writing new tests using video-test.js) -->
 <script src="video-test.js" type="text/javascript"></script>
 
 <iframe style="width: 400px; height: 300px; border: 0px;" id="container"> </iframe>
 
 <script type="text/javascript">
 var iframe = document.getElementById("container");
 
 function timeupdate(event) {
     var video = event.target;
     controls = internals.shadowRoot(video).firstChild.firstChild;
     testExpected("controls.offsetTop + controls.offsetHeight", video.offsetHeight, "<=");
     testRunner.notifyDone();
 };
 
 function start() {
     var iframeDocument = document.getElementById("container").contentDocument;
     var video = iframeDocument.querySelector("video");
     video.addEventListener("timeupdate", timeupdate);
 };
 
 iframe.onload = start;
 iframe.src = findMediaFile("video", "content/test");
 </script>