Document calls to the "rules for updating the text track rendering"

Source/core/html/track/TextTrackContainer.cpp

 /*
  * Copyright (C) 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 43 matching lines @@
     return new LayoutTextTrackContainer(this);
 }
 
 void TextTrackContainer::updateDisplay(HTMLMediaElement& mediaElement)
 {
     if (!mediaElement.closedCaptionsVisible()) {
         removeChildren();
         return;
     }
 
+    // http://dev.w3.org/html5/webvtt/#dfn-rules-for-updating-the-display-of-webvtt-text-tracks
+
     // 1. If the media element is an audio element, or is another playback
     // mechanism with no rendering area, abort these steps. There is nothing to
     // render.
     if (isHTMLAudioElement(mediaElement))
         return;
 
     // 2. Let video be the media element or other playback mechanism.
     HTMLVideoElement& video = toHTMLVideoElement(mediaElement);
 
     // 3. Let output be an empty list of absolutely positioned CSS block boxes.
@@ skipping 41 matching lines @@
     }
 
     // 11. Return output.
     if (hasChildren())
         removeInlineStyleProperty(CSSPropertyDisplay);
     else
         setInlineStyleProperty(CSSPropertyDisplay, CSSValueNone);
 }
 
 } // namespace blink