Implement <video controls> dodging for text track layout

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 61 matching lines @@
     // 3. Let output be an empty list of absolutely positioned CSS block boxes.
 
     // 4. If the user agent is exposing a user interface for video, add to
     // output one or more completely transparent positioned CSS block boxes that
     // cover the same region as the user interface.
 
     // 5. If the last time these rules were run, the user agent was not exposing
     // a user interface for video, but now it is, let reset be true. Otherwise,
     // let reset be false.
 
-    // FIXME: Implement step 4 and 5.
-
     // 6. Let tracks be the subset of video's list of text tracks that have as
     // their rules for updating the text track rendering these rules for
     // updating the display of WebVTT text tracks, and whose text track mode is
     // showing or showing by default.
     // 7. Let cues be an empty list of text track cues.
     // 8. For each track track in tracks, append to cues all the cues from
     // track's list of cues that have their text track cue active flag set.
     CueList activeCues = video.cueTimeline().currentlyActiveCues();
 
     // 9. If reset is false, then, for each text track cue cue in cues: if cue's
@@ skipping 14 matching lines @@
         if (!cue->track() || !cue->track()->isRendered() || !cue->isActive())
             continue;
 
         cue->updateDisplay(*this);
     }
 
     // 11. Return output.
 }
 
 } // namespace blink