Move activeCues ownership to TextTrack

Source/core/html/track/TextTrack.cpp

 /*
  * Copyright (C) 2011 Google Inc.  All rights reserved.
  * Copyright (C) 2011, 2012, 2013 Apple 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 214 matching lines @@
 
     for (auto& newCue : listOfNewCues) {
         newCue->setTrack(this);
         cues->add(newCue.release());
     }
 
     if (cueTimeline() && mode() != disabledKeyword())
         cueTimeline()->addCues(this, cues);
 }
 
-TextTrackCueList* TextTrack::activeCues() const
+TextTrackCueList* TextTrack::activeCues()
 {
     // 4.8.10.12.5 If the text track mode ... is not the text track disabled mode,
     // then the activeCues attribute must return a live TextTrackCueList object ...
     // ... whose active flag was set when the script started, in text track cue
     // order. Otherwise, it must return null. When an object is returned, the
     // same object must be returned each time.
     // http://www.whatwg.org/specs/web-apps/current-work/#dom-texttrack-activecues
-    if (m_cues && m_mode != disabledKeyword())
-        return m_cues->activeCues();
-    return nullptr;
+    if (!m_cues || m_mode == disabledKeyword())
+        return nullptr;
+
+    if (!m_activeCues)
+        m_activeCues = TextTrackCueList::create();
+
+    m_cues->collectActiveCues(*m_activeCues);
+    return m_activeCues.get();
 }
 
 void TextTrack::addCue(PassRefPtrWillBeRawPtr<TextTrackCue> prpCue)
 {
     ASSERT(prpCue);
     RefPtrWillBeRawPtr<TextTrackCue> cue = prpCue;
 
     // TODO(93143): Add spec-compliant behavior for negative time values.
     if (std::isnan(cue->startTime()) || std::isnan(cue->endTime()) || cue->startTime() < 0 || cue->endTime() < 0)
         return;
@@ skipping 204 matching lines @@
 }
 
 Node* TextTrack::owner() const
 {
     return mediaElement();
 }
 
 DEFINE_TRACE(TextTrack)
 {
     visitor->trace(m_cues);
+    visitor->trace(m_activeCues);
     visitor->trace(m_regions);
     visitor->trace(m_trackList);
     TrackBase::trace(visitor);
     EventTargetWithInlineData::trace(visitor);
 }
 
 } // namespace blink