Separate the text track container from the media controls

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 27 matching lines @@
 
 TextTrackContainer::TextTrackContainer(Document& document)
     : HTMLDivElement(document)
 {
 }
 
 PassRefPtrWillBeRawPtr<TextTrackContainer> TextTrackContainer::create(Document& document)
 {
     RefPtrWillBeRawPtr<TextTrackContainer> element = adoptRefWillBeNoop(new TextTrackContainer(document));
     element->setShadowPseudoId(AtomicString("-webkit-media-text-track-container", AtomicString::ConstructFromLiteral));
-    element->setInlineStyleProperty(CSSPropertyDisplay, CSSValueNone);
     return element.release();
 }
 
 LayoutObject* TextTrackContainer::createLayoutObject(const LayoutStyle&)
 {
     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.
 
+    // Note: This is a layout algorithm, expressed terms of appending CSS block
+    // boxes to output, and the "apply WebVTT cue settings" part is implemented
+    // in LayoutVTTCue. Here we merely create the DOM tree from which the layout
+    // tree is built and append it to this TextTrackContainer.
+
     // 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.
 
-    // There is nothing to be done explicitly for 4th and 5th steps, as
-    // everything is handled through CSS. The caption box is on top of the
-    // controls box, in a container set with the -webkit-box display property.
+    // TODO(philipj): 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.
     const CueList& activeCues = video.cueTimeline().currentlyActiveCues();
 
@@ skipping 14 matching lines @@
 
         ASSERT(cue->isActive());
         if (!cue->track() || !cue->track()->isRendered() || !cue->isActive())
             continue;
 
         cue->updateDisplay(*this);
         cue->updatePastAndFutureNodes(movieTime);
     }
 
     // 11. Return output.
-    if (hasChildren())
-        removeInlineStyleProperty(CSSPropertyDisplay);
-    else
-        setInlineStyleProperty(CSSPropertyDisplay, CSSValueNone);
+    // See the note for step 3 for why there is no output to return.
 }
 
 } // namespace blink