Eliminate calls to TextTrackCue::setIsActive outside of CueTimeline

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 271 matching lines @@
     // The removeCue(cue) method of TextTrack objects, when invoked, must run the following steps:
 
     // 1. If the given cue is not currently listed in the method's TextTrack
     // object's text track's text track list of cues, then throw a NotFoundError exception.
     // 2. Remove cue from the method's TextTrack object's text track's text track list of cues.
     if (cue->track() != this || !m_cues || !m_cues->remove(cue)) {
         exceptionState.throwDOMException(NotFoundError, "The specified cue is not listed in the TextTrack's list of cues.");
         return;
     }
 
-    cue->setIsActive(false);
-    cue->removeDisplayTree();
+    // If the cue is active, a timeline needs to be available.
+    ASSERT(!cue->isActive() || cueTimeline());
 
     cue->setTrack(0);
+
     if (cueTimeline())
         cueTimeline()->removeCue(this, cue);
 }
 
 VTTRegionList* TextTrack::ensureVTTRegionList()
 {
     if (!m_regions)
         m_regions = VTTRegionList::create();
 
     return m_regions.get();
@@ skipping 57 matching lines @@
     if (!m_regions || !m_regions->remove(region)) {
         exceptionState.throwDOMException(InvalidStateError, "Failed to remove the specified region.");
         return;
     }
 
     region->setTrack(0);
 }
 
 void TextTrack::cueWillChange(TextTrackCue* cue)
 {
-    if (!cueTimeline())
-        return;
-
     // The cue may need to be repositioned in the media element's interval tree, may need to
     // be re-rendered, etc, so remove it before the modification...
-    cueTimeline()->removeCue(this, cue);
+    if (cueTimeline())
+        cueTimeline()->removeCue(this, cue);
 }
 
 void TextTrack::cueDidChange(TextTrackCue* cue)
 {
-    if (!cueTimeline())
-        return;
-
     // Make sure the TextTrackCueList order is up-to-date.
+    // FIXME: Only need to do this if the change was to any of the timestamps.
     ensureTextTrackCueList()->updateCueIndex(cue);
 
-    // ... and add it back again if the track is enabled.
+    // Since a call to cueDidChange is always preceded by a call to
+    // cueWillChange, the cue should no longer be active when we reach this
+    // point (since it was removed from the timeline in cueWillChange).
+    ASSERT(!cue->isActive());
+
     if (m_mode == disabledKeyword())
         return;
 
-    cueTimeline()->addCue(this, cue);
+    // ... and add it back again if the track is enabled.
+    if (cueTimeline())
+        cueTimeline()->addCue(this, cue);
 }
 
 int TextTrack::trackIndex()
 {
     ASSERT(m_trackList);
 
     if (m_trackIndex == invalidTrackIndex)
         m_trackIndex = m_trackList->getTrackIndex(this);
 
     return m_trackIndex;
@@ skipping 63 matching lines @@
 DEFINE_TRACE(TextTrack)
 {
     visitor->trace(m_cues);
     visitor->trace(m_regions);
     visitor->trace(m_trackList);
     TrackBase::trace(visitor);
     EventTargetWithInlineData::trace(visitor);
 }
 
 } // namespace blink